HTML

What is HTML?

Hypertext Markup Language (HTML) is the standard markup language for creating web pages and web applications.

Web browsers receive HTML documents from a web server or from local storage and render them into multimedia web pages.

HTML describes the structure of a web page.

The current HTML version is HTML5

A markup language is a system for annotating a document in a way that is syntactically distinguishable from the text. Instructions are expressed directly by tags.

Open the following news and define the different parts of the document structure.

Looks like this document has the following sections:

A main title: ’Black Panther’ stays strong with \$108M in second weekend
A picture
A picture description: This image released by Disney shows a scene from Marvel Studios' "Black Panther." Matt Kennedy / AP
Secondary title: NEW YORK — “Black Panther” has scored one of the best second weekends ever with an estimated \$108 million in ticket sales.
Text: Studio estimates Sunday say “Black Panther” is still performing as one of the top blockbusters of all time. This weekend’s result makes Ryan Coogler’s Marvel sensation only the fourth film to earn $100 million in its second weekend, along with “Star Wars: The Force Awakens,” “Jurassic World” and “The Avengers.” Of those, only “The Force Awakens” had a better second weekend. In two weeks of release, “Black Panther” has grossed $400 million domestically and $704 million worldwide. Of new releases, faring the best is the Warner Bros. comedy “Game Night,” starring Jason Bateman and Rachel McAdams. It debuted with $16.6 million. The well-reviewed sci-fi thriller “Annihilation” opened with \$11 million.
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Finally, this is how the news HTML code looks like:

Tag Structure

As HTML is a markup language we'll use tags to create HTML elements that will show the user the different document sections and content.
A tag will have the following parts:
- The < character defines the initial part of our tag
- Then well add the tagname that we want to use
- At the end we'll use the > character
- We can call this void or empty element as it doesn't have any content
```
<tagname></tagname>
```
There're other tags that will have content
To add content we just write it after the > character
```
<tagname>Content of our tag</tagname>
```
In this case the first tag is working as an opening one
We need to close this structure to let the browser know that we finished definening this structure
Closing tags are pretty similar to the opening ones but with a minor difference
Add a / character after the < and the tagname
```
<tagname>Content of our tag</tagname>
```
We can write this in a different format too
Using identation it's a good practice when we code as it allows us to see complex structures in a simpler way
```
<tagname>
  Content of our tag
</tagname>
```
We have 2 different types of tags:
- Void or empty - just 1 tag
- With content - need the opening and closing tags

Tag attribute

Tag attributes are additional values that configure the tags or adjust their behavior in various ways to meet the criteria the users want.
The attributes will have an attribute name and a value
```
attribute="value"
```

Attributes are part of the tag

<tagname attribute="value">
  <tagname attribute="value">Content of our tag</tagname></tagname
>

HTML defines elements attributes
Some attributes are global
The id attribute allow us to unique identify an element in a document
We can add an id attribute to any HTML element

There must only one element by id

<tagname id="first-element">
  <tagname id="second-element">Content of our tag</tagname></tagname
>

The class attribute accepts a CSS class name

We can use the class attribute to identify many elements by the same criteria

<tagname class="red">Text in red</tagname>
<tagname class="red">Text in red</tagname>
<tagname class="red">Text in red</tagname>
<tagname class="red">Text in red</tagname>
<tagname class="red">Text in red</tagname>

Tag with tags!

Also, we can have tags as content from other tags:

<tagname>
  <tagname>Hi I'm a title</tagname>
  <tagname> </tagname
></tagname>

Using tags inside other tags we can create more complex structures
This looks great but it doesn't make sense as all the tags have the same name

HTML Tags

Now that we know how tags works we only need to know the HTML tags names and attributes
Check the MDN site to se a complete list of HTML elements reference

HTML document structure

The first tag we'll learn is the DOCTYPE tag
It's an empty tag as it doesn't have content
By using this tag the browser knows the version of HTML that we are using
The browser won't render this tag

HTML5 Doctype

<!DOCTYPE html>

HTML

The html element represents the root (top-level element) of an HTML document, so it is also referred to as the root element. All other elements must be descendants of this element.
MDN html doc

<html></html>

HEAD

The head element provides general information (metadata) about the document, including its title and links to its scripts and style sheets.
MDN head doc

<head></head>

Title

The Title element defines the title of the document, shown in a browser's title bar or on the page's tab. It can only contain text, and any tags contained within are ignored.
It's part of the head element
MDN title doc

<head>
  <title>Document title!</title>
</head>

BODY

The body Element represents the content of an HTML document. There can be only one <body> element in a document.
We can write any content or other HTML elements between the html tags
MDN body doc

<body></body>

Basic HTML file

Example:

<!DOCTYPE html>
<html>
  <head>
    <title>Document title</title>
  </head>
  <body>
    Text inside the HTML body tag
  </body>
</html>

Practice

Exercise 1

Heading Elements

HTML has 6 title levels
The title tag name is the letter h and the title number (h1, h2, h3, h4, h5, h6)
By default the browser will show the h1 much bigger than the h6
It's a good practice to respect the titles order by Hierarchy
MDN heading elements doc

Example:

<h1>Main title</h1>
<h2>Secondary title</h2>
<h3>Other title</h3>
<h4>Other title</h4>
<h5>Other title</h5>
<h6>Other title</h6>

Paragraph

The p tagname represents a paragraph
This tag accepts content so we'll have an open and close tags
The paragraph tag is a block element
By default the browser will show block elements one below the other
The browser will render only a space character even if we write many
We can use HTML entity to display the space character
MDN paragraph doc

Example

<p>Paragraph content.</p>
<p>Paragraph content.</p>
<p>Text with some &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; spaces</p>

Practice

Exercise 2

Containers

Div

The content division element div is the generic container
This tag has no effect on the content or layout until styled using CSS
It's used to group content so it can be easily styled
By default this is a block element and begin on new lines
MDN div doc

Span

The span element is a generic inline container for phrasing content, which does not inherently represent anything.
It can be used to group elements for styling purposes
Inline elements can start anywhere in a line

Example:

<span>This is a inline element</span>
<span>Next element inline and it's right next the previous one</span>
<p>This paragraph has a <span>section</span></p>

Inline vs Block elements

block-level elements may contain inline elements and other block-level elements.
Inherent in this structural distinction is the idea that block elements create "larger" structures than inline elements.
Inline elements are those which only occupy the space bounded by the tags defining the element, instead of breaking the flow of the content.
Generally, inline elements may contain only data and other inline elements. You can't put block elements inside inline elements.
By default, inline elements do not force a new line to begin in the document flow. Block elements, on the other hand, typically cause a line break to occur (although, as usual, this can be changed using CSS).
MDN Block-level_elements
MDN Inline_elements

Comments

In most programming languages, there is a mechanism available to write comments in the code
Comments are ignored by the browser and are invisible to the user
Their purpose is to allow you to include comments in the code to say how your code works, what the different parts of the code do, etc.
We can write inline or multiline comments

Example:

<!-- Inline comment -->

<!-- 
  Multiline Comment
  Multiline Comment
  Multiline Comment
  Multiline Comment
  Multiline Comment
  Multiline Comment
-->

<!-- <p>The browser won't render this paragraph</p> -->

Line Break

The br element produces a line break in our text (carriage-return)
It is useful where the division of lines is significant
MDN br doc

Example:

<p>
  This text will have a line break<br />
  and then we keep on writing
</p>
<br />
<br />
<p>
  We can use a line break in any <br />
  part of our documents body
</p>

Horizontal Rule

The hr element represents a thematic break between paragraph-level elements
It has been presented as a horizontal rule or line
MDN hr doc

Example:

<h1>Main title</h1>
<h2>Subtitle</h2>
<hr />
<p>Rest of the content</p>

Practice

Exercise 3

Text Format

HTML has some tags to describe how the text should be
The strong element indicates that its contents have strong importance, seriousness, or urgency.
Browsers typically render the contents in bold type.
Remember that we'll use CSS for bold font weight

Example:

<strong>This is a very important text!!</strong>

Lists

As web developers we'll use lists for many different things
HTML has 3 different list types:
- Unordered
- Ordered
- Description or definition

Unordered list

The ul element represents an unordered list of items
By default it will be rendered as a bulleted list
We'll use this type of list when we don't care about items order
Each item is a list item or li element
MDN ul doc
MDN li doc

Example:

<ul>
  <li>First List Item</li>
  <li>Second List Item</li>
  <li>Third List Item</li>
</ul>

Ordered list

The ol element represents an ordered list of items
By default it will be rendered as a numbered list
We'll use this type of list when we care about the items order
This type of list also accepts li elements as children
MDN ol doc

Example:

<ol>
  <li>Order Item</li>
  <li>Order Item</li>
  <li>Order Item</li>
</ol>

Description or definition list

The dl element represents a description list
The element encloses a list of groups of terms (dt element) and descriptions (dd elements)
Common uses for this element are to implement a glossary or to display metadata (a list of key-value pairs)
MDN dl doc
MDN dt doc
MDN dd doc

Example:

<dl>
  <dt>Term</dt>
  <dd>Definition</dd>
</dl>

Nested list

List can be nested inside list items
We can use any list type
Very helpful and used to create sites menus adding CSS

mindblown

Example:

<ul>
  <li>Unordered list item</li>
  <li>
    <ol>
      <li>Order list item</li>
      <li>Order list item</li>
      <li>Order list item</li>
    </ol>
  </li>
</ul>

Practice

Exercise 4

Hyperlink

The a element (or anchor element) creates a hyperlink to other web pages, files, locations within the same page, email addresses, or any other URL.
This element has a href attribute that contains a URL or a URL fragment that the hyperlink points to
Between the opening and the closing tag we can add the link content that the user will click on
As content we can put other HTML elements like an image tag

Example:

<a href="other_file.html">Click me I'm a link!!</a>
<a href="my_dog.jpg">Link to my dog picture</a>
<a href="video.avi">Link to my video</a>

External links

In some cases we need to link our HTML documents with external files or other resources
We can do this by using the external URL's as href values

Example:

<a href="http://google.com">Go to google.com</a>

Target attribute

The a has a target attribute that specifies where to display the linked URL.
The following keywords have special meanings:
- _self: Load the URL into the same browsing context as the current one. This is the default behavior.
- _blank: Load the URL into a new browsing context. This is usually a tab, but users can configure browsers to use new windows instead.
- _parent: Load the URL into the parent browsing context of the current one. If there is no parent, this behaves the same way as _self.
- _top: Load the URL into the top-level browsing context (that is, the "highest" browsing context that is an ancestor of the current one, and has no parent). If there is no parent, this behaves the same way as _self.
For now we'll use only _blank as it's the one we use the most

Example:

<a href="http://www.comit.org" target="_blank">ComIT</a>
<a href="http://www.comunidadit.org" target="_blank">Comunidad IT</a>

Absolute & relative URLs

We can define absolute or relative Urls
Let's check this MDN URL guide to understand better what's and absolute URL

Example:

<a href="http://yahoo.com">Abrir Yahoo</a>
<a href="c:\Users\my_name\my_cv.pdf">Look at my CV</a>

Links can have a relative URL or path
In this type of URLs we need to know the relationship between files
To access to the root of our site we can use the following relative path
Absolute and relatives URLs and Paths will work with any element that need an URL or path to work (imgs, video, audio and more)

Example:

<a href="/">Go Home</a>

/ (root of our folder)
|
|-- index.html
|-- about.html

If we have to files that are siblings or in the same path level we can use the filename as link

Example:

To link index.html with about.html
<a href="about.html">About</a>

To link about.html with index.html
<a href="index.html">Go Home</a>

As index is the main file in our site we could use the root
<a href="/">Go Home</a>

/ (root of our folder)
|-- about/
|   |--- about.html
|
|-- index.html

To link a file that it's inside a folder we'll use the foldername/filename

Example:

To link index.html with the about.html <a href="about/about.html">About</a>

Also we can link files from inside a folder to another that's outside
We will add as many ../ as folders we need to exit

Example:

To link about.html to index.html first we need to exit the about folder
<a href="../index.html">Go home</a>

/ (root of our folder)
|-- about/
|   |-- other_folder/
|     |--- about.html
|
|-- index.html

Example:

With this folder structure: To link from index.html to about.html we'll use both
folder names
<a href="about/other_folder/about.html">About</a>

To link about.html to index.html we need to exit 2 folders (../../filename)
<a href="../../index.html">Go home</a>

Mailto

We can use links to configure to send an email
The browser will try to open the default email app if we set the href value to mailto:account@domain.com

<a href="mailto:pablo@comit.org">Contact me</a>

Anchor

We can use links to navigate to anchor points and into a selected document part
If the URL has an anchor the browser will lookup for that document section
To accomplish this task we need to combine the a element and href, name attributes
The # works as anchor symbol (remember the URLs MDN guide)

Example

First we'll create a link with the anchor href
<a href="#news">News Section</a>

Then we need to create the anchor by using the name attribute
<a name="news"></a>

We created an empty link with the news attribute. As they are on the same
document the browser will try to navigate to the news anchor. To be able to see
this magic working we need to create long documents Also we can navigate to a
different document section:
<a href="news.html#nhl">NHL news section</a>

Practice

Exercise 5

Exercise 6

Images

The img element embeds an image into the document
It's only a one tag element as it doesn't allow content (other elements or text)
The src attribute accepts an image filename / path
The img is an inline element
By default the placeholder will have the image size
We must use optimized images to avoid big files
The browser knows how to render different image types: jpg, png & gif
Image optimization - Google Developers
MDN img doc

Example

<img src="mypicture.jpg" />

We can use absolute or relative paths/urls as src value

Example

Relative example:
<img src="img/mypicture.jpg" />

Go one folder level back, then enter the img folder and get mypicture file
<img src="../img/mypicture.jpg" />

Absolute URL:
<img
  src="http://images6.fanpop.com/image/photos/39500000/il-570xN-917420114-2kdu-rick-and-morty-39567961-300-370.jpg"
/>

The img has a height and width attribute
This attributes accepts the intrinsic width & height of the image in pixels
HTML5 doesn't accept other types of values
Keep in mind the image ratio when using this attributes

<img src="mypicture.jpg" height="300" width="300" />

The alt attribute defines the alternative text describing the image.
Users will see this text displayed if the image URL is wrong, the image is not in one of the supported formats, or if the image is not yet downloaded.
Also, screen readers will use this attribute to describe the image
Adding this attribute to our images is a good practice

Example

<img src="coding.jpg" alt="Developers working on a new project" />

We can also add a global attribute to our images to describe it better
The title contains a text representing advisory information related to the element it belongs to.
Such information can typically, but not necessarily, be presented to the user as a tooltip.

Example

<img src="coding.jpg" alt="Developers working on a new project" title="Nerds" />

Image alt vs title - Using alt title attributes in image tags

Figure & Figure caption

the figure element represents self-contained content, frequently with a caption (figcaption), and is typically referenced as a single unit.
As figure content we'll add an image (img) and a caption (figcaption) elements
Older browser won't know how to show this element but they will render the image
MDN figure doc
Test your browser

Example

<figure>
  <img
    src="coding.jpg"
    alt="Developers working on a new project"
    title="Nerds"
  />
  <figcaption>Developers working on a new project</figcaption>
</figure>

Practice

Exercise 7

Table

The table element represents tabular data — that is, information presented in a two-dimensional table comprised of rows and columns of cells containing data
Our table will have rows (table rows or tr) and columns (table data or td)
MDN table doc
MDN tr doc
MDN td doc

Example

<table>
  <tr>
    <td>1</td>
    <td>2</td>
  </tr>
  <tr>
    <td>3</td>
    <td>4</td>
  </tr>
</table>

In this example will see a table with 1 and 2 on the first row and 3 and 4 in the second one
If we need to have an empty cell we still need to add it as part of the table

Example

<table>
  <tr>
    <td>1</td>
    <td>2</td>
  </tr>
  <tr>
    <td>3</td>
    <td></td>
  </tr>
</table>

Practice

Exercise 8

Also we can use a th to define a cell as header
MDN th doc

Example

<table>
  <tr>
    <th>Name</th>
    <th>Last Name</th>
  </tr>
  <tr>
    <td>Dale</td>
    <td>Hawerchuk</td>
  </tr>
</table>

We can use the following elements to define table sections: thead, tbody & tfoot
The thead element defines a set of rows defining the head of the columns of the table
The tbody encapsulates a set of table row (tr elements, indicating that they comprise the body of the table)
The tfoot element defines a set of rows summarizing the columns of the table
A well structured table has all 3 sections
This is also useful for the screen readers
We can combine the thead and th element

Example

<table>
  <thead>
    <tr>
      <th>Header 1 - 1</th>
      <th>Header 1 - 2</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Body 1 - 1</td>
      <td>Body 1 - 2</td>
    </tr>
    <tr>
      <td>Body 2 - 1</td>
      <td>Body 2 - 2</td>
    </tr>
  </tbody>
  <tfoot>
    <tr>
      <td>Foot 1 - 1</td>
      <td>Foot 1 - 2</td>
    </tr>
  </tfoot>
</table>

Practice

Exercise 9

Make the tables happier!

The table element has some attributes that will allow us to add color and other visual effects
This attributes belong to previous HTML versions but we can still use them
Remember that we only should use HTML to structure our documents and add CSS to change the way things look
The border attribute defines, in pixels, the size of the frame surrounding the table. If set to 0, the frame attribute is set to void
The bgcolor attribute defines the background color of a table. It consists of a 6-digit hexadecimal code as defined in sRGB and is prefixed by '#'
We can use any web color as bgcolor
Each cell can have a different bgcolor value

Example

<table border="1" bgcolor="gray">
  <thead>
    <tr>
      <th>Header content 1</th>
      <th>Header content 2</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td bgcolor="white">Content with white background</td>
      <td>Body content</td>
    </tr>
  </tbody>
  <tfoot>
    <tr>
      <td>Footer section 1</td>
      <td>Footer section 2</td>
    </tr>
  </tfoot>
</table>

We can use the width attribute to set the table width
The cells also have a with attribute and the table will try to keep the same size for the rest of the cells in the same column
The cellpadding attribute defines the space between the content of a cell and its border, displayed or not
The cellspacing attribute defines the size of the space between two cells in a percentage value or pixels

Example

<table width="800" cellpadding="10" cellspacing="10">
  <thead>
    <tr>
      <th width="100">Header 1</th>
      <th>Header 2</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Content 1</td>
      <td>Content 2</td>
    </tr>
  </tbody>
  <tfoot>
    <tr>
      <td>Footer 1</td>
      <td>Footer 2</td>
    </tr>
  </tfoot>
</table>

To provide additional control over how cells fit into (or span across) columns, both th and td support the colspan attribute, which lets you specify how many columns wide the cell should be, with the default being 1.
Similarly, you can use the rowspan attribute on cells to indicate they should span more than one table row.

Example

<table border="1">
  <tr>
    <td rowspan="2">1 Column</td>
    <td>middle value</td>
    <td>middle value</td>
    <td rowspan="2">1 Column</td>
  </tr>
  <tr>
    <td>middle value</td>
    <td>middle value</td>
  </tr>
  <tr>
    <td colspan="4">Just 1 column for 4 spaces</td>
  </tr>
</table>

Practice

Exercise 10

Favicon

Favicon is an icon that we can show on our browser window (tabs)
Most browsers will support .ico, .gif or .png but using the ICO format will ensure it works as far back as Internet Explorer 6
There are lots of other icon types to consider these days as well and you can read more about it on the MDN site

<head>
  <title>My site with a great Favicon!</title>
  <link rel="shortcut icon" href="favicon.ico" type="image/x-icon" />
</head>

Practice

Personal Site

Forms

The form element represents a document section that contains interactive controls for submitting information to a web server
We can find them everywhere and in different styles too!

Search engines:

Google: Google

Twitter: Twitter search

Youtube: Youtube search

Comments / Posts:

Twitter post:

Medium: Medium post

Facebook: Medium post

Log in / sign up

Facebook: Facebook post

The form element has 3 important attributes:
- action: the URI of a program that processes the form information
- method: the HTTP method that the browser uses to submit the form: get or post
  - get: corresponds to the HTTP GET method; form data are appended to the action attribute URI with a '?' as separator, and the resulting URI is sent to the server
  - post: corresponds to the HTTP POST method ; form data are included in the body of the form and sent to the server
- enctype: when the value of the method attribute is post, enctype is the MIME type of content that is used to submit the form to the server. Possible values:
  - Default: 'application/x-www-form-urlencoded'
  - To send file content: 'multipart/form-data'
  - Just text: 'text/plain'
MDN form doc

<form
  action="create_user.php"
  method="get"
  enctype="application/x-www-form-urlencoded"
>
  My Form
</form>

A form can have many different input types elements
We can submit the form using a button to execute the form action and send the form data
Many programing languages can process form data server side like C#, Java, JavaScript, PHP, Ruby and others
Each input will have a name attribute so we can identify it
The user will get a response after submitting and processing the data server side

Inputs

The input element is used to create interactive controls for web-based forms in order to accept data from the user
How it works varies considerably depending on the value of its type attribute
If this attributes is not specified, the default type adopted is text
The available types are as follows: button, checkbox, color, date, datetime-local, email, file, hidden, image, month, number, password, range, reset, search, submit, tel, text, time, url, week
MDN input doc

Example:

<form>
  <input type="input-type" name="variable-name" />
</form>

Text

Create basic single-line text fields (name, lastname, username, address)
Use the type value of text to define this type of input
You must remember to include name attribute on the input element, otherwise the text field's value won't be included with the submitted data
MDN input type text doc

Example:

<form>
  <input type="text" name="username" />
</form>

The value attribute contains the value of the text input
The user will see any predefined value
To clear the input the user will have to manually delete the input content

Example:

<input type="text" name="username" value="harryp" />

The placeholder attribute is typically rendered in a lighter color than the element's foreground color, and automatically vanishes when the user begins to enter text into the field

Example:

<input type="text" name="username" placeholder="Please input a username" />

The size attribute specified the number of characters the text input can display at a time
This affects the width of the element, letting you specify the width in terms of characters rather than pixels
As it's only a visual effect we can update it with CSS

Example:

<input type="text" name="username" value="harryp" size="20" />

You can specify a minimum length (in characters) for the entered value using the minlength attribute
Similarly, use maxlength to set the maximum length of the entered value, in characters

Example:

<input
  type="text"
  name="username"
  value="harryp"
  minlength="3"
  maxlength="20"
/>

If you try to submit the form with less than 4 characters, you'll be given an appropriate error message (which differs between browsers).
If you try to enter more than 8 characters, the browser won't let you.
If you specify a minlength but do not specify required, the input is considered valid, since the user is not required to specify a value

Password

The input type passowrd provide a way for the user to securely enter a password
The element is presented as a one-line plain text editor control in which the text is obscured so that it cannot be read, usually by replacing each character with a symbol such as the asterisk ("*") or a dot ("•")
Set the type attribute to password
We can use the name, value, size, minlength & maxlength attributes
Remember that this hidden text is just a visual effect
Use HTTPS to send client data to the server
MDN input type password doc

Example:

<form>
  <input type="password" name="pass" />
</form>

Submit button

The input type submit is just a button that submits the form
This type of element's value attribute contains the button's label
If you don't specify a value, the button will have a default label, chosen by the user agent
MDN input submit doc

Example:

<form>
  <input type="submit" value="Submit this form" />
</form>

Practice

Exercise 11

Labels

The label element represents a caption for an item in a user interface
A label can be associated with a control either by placing the control element inside the label element, or by using the for attribute
Such a control is called the labeled control of the label element
One input can be associated with multiple labels
MDN label doc

Example:

<form>
  <label>Name:</label>
  <input type="text" name="name" />
  <label>Surname:</label>
  <input type="text" name="surname" />
</form>

Also we could use it this way:

Example:

<form>
  <label>
    Name:
    <input type="text" name="name" />
  </label>
  <label>
    Surname:
    <input type="text" name="surname" />
  </label>
</form>

The label element has a for attribute
Once we set the for attribute, the user will be able to click on the label element to get focus in the set for value
The id of a label form-related element in the same document as the label element.
The first such element in the document with an ID matching the value of the for attribute is the labeled control for this label element

Example:

<form>
  <label for="nameid">Name:</label>
  <input type="text" name="name" id="nameid" />
  <label for="surnameid">Surname:</label>
  <input type="text" name="surname" id="surnameid" />
</form>

Fieldset

The fieldset element is used to group several controls as well as labels within a web form
MDN fieldset doc

Example

<form>
  <fieldset>
    <label>Name:</label>
    <input type="text" name="name" />
    <label>Surname:</label>
    <input type="text" name="surname" />
  </fieldset>
</form>

The legend element represents a caption for the content of its parent fieldset

Example

<form>
  <fieldset>
    <legend>User Form</legend>
    <label>Name:</label>
    <input type="text" name="name" />
    <label>Surname:</label>
    <input type="text" name="surname" />
  </fieldset>
</form>

Radio buttons

The input type radio elements are generally used in radio groups—collections of radio buttons describing a set of related options
Only one radio button in a given group can be selected at the same time
Radio buttons are typically rendered as small circles, which are filled or highlighted when selected
To define a radio group each of the radio buttons in the group must have same name attribute
The user will see a legend next to each radio button by using a label element or just plain text
MDN input type radio doc

Example

<form>
  Are you a Riders Fan?
  <input type="radio" name="ridersfan" value="true" /> Oh Yeahhhhhh, Go
  Riders!!! <input type="radio" name="ridersfan" value="false" /> No
</form>

Use the checked attribute with a checked value to select the default selected value
In HTML5 when the attribute name and value is the same we can just add the attribute checked

Example

<form>
  Are you a Riders Fan?
  <input type="radio" name="ridersfan" value="true" checked="checked" /> Oh
  Yeahhhhhh, Go Riders!!!
  <input type="radio" name="ridersfan" value="false" /> No
  <!-- <input type="radio" name="ridersfan" value="true" checked> Oh Yeahhhhhh, Go Riders!!! -->
</form>

Checkboxes

The input elements of type checkbox are rendered by default as square boxes that are checked (ticked) when activated
They allow you to select single values for submission in a form (or not).
Radio buttons are similar to checkboxes, but with an important distinction:
radio buttons are grouped into a set in which only one radio button can be selected at a time, whereas checkboxes allow you to turn single values on and off. Where multiple controls exist, radio buttons allow one to be selected out of them all, whereas checkboxes allow multiple values to be selected.
To select multiple values we need to use the same name input
Use the value attribute to set each input selected value
The checked attribute and value works the same way as radio buttons
MDN input type checkbox doc

Example

<form>
  Select your favourite Harry Potter wizards
  <input
    type="checkbox"
    name="wizards"
    value="harry potter"
    checked="checked"
  />
  Harry Potter
  <input type="checkbox" name="wizards" value="hermione granger" checked />
  Hermione Granger
  <input type="checkbox" name="wizards" value="ron weasley" /> Ron Weasley
  <input type="checkbox" name="wizards" value="aberforth dumbledore" />
  Aberforth Dumbledore
</form>

Hidden

The input elements of type hidden let web developers include data that cannot be seen or modified by users when a form is submitted
A good example: the ID of the content that is currently being ordered or edited, or a unique security token
Hidden inputs are completely invisible in the rendered page, and there is no way to make it visible in the page's content
A user will be able to see them on the source code

Example:

<form>
  <input type="hidden" name="product-id" value="1" />
</form>

Image buttons

The input elements of type image are used to create graphical submit buttons
We can use a button image instead of the default submit one
To define the image we use the src attribute (as the image element)
MDN input type image doc

Example:

<form>
  <input type="image" src="create_user_button.png" />
</form>

To change the image size we can use the height & width attributes
We'll use CSS to change the way elements have to look (friendly reminder)

Practice

Exercise 12

Text area

The textarea element represents a multi-line plain-text editing control
This element has an opening and close tag
MDN input textarea doc

Example

<textarea name="about">Rick Sanchez it's a great scientific..</textarea>

Use the placeholder attribute to let the user know what to input

Example

<textarea
  name="about"
  placeholder="Please let us know about yourself"
></textarea>

The cols attribute sets the textarea amount of columns
The rows attribute sets the textarea amount of lines

Example

<textarea name="about" cols="10" rows="2">Initial textarea text!</textarea>

Select

The select element represents a control that provides a menu of options
The option element is used to define an item contained in a select element
As such, option can represent menu items in popups and other lists of items in an HTML document
MDN input select doc
MDN input option doc

Example

<form>
  <select name="options">
    <option>First Item</option>
    <option>Second Item</option>
  </select>
</form>

The option element uses a value attribute to define the value the user selects
Also we can show the user a different text as an option content

Example

<form>
  <select name="countries">
    <option value="">Please select a Country</option>
    <option value="arg">Argentina</option>
    <option value="bra">Brasil</option>
    <option value="chl">Chile</option>
    <option value="can">Canada</option>
  </select>
</form>

We can use the selected attribute to select the default selected value
This attribute uses the selected value and is the same attribute name we can just use the attribute name without a value (example: selected="selected")
By default the first option is going to be selected

Example

<form>
  <select name="countries">
    <option value="">Please select a Country</option>
    <option value="arg">Argentina</option>
    <option value="bra">Brasil</option>
    <option value="chl">Chile</option>
    <option value="can" selected="selected">Canada</option>
  </select>
</form>

OR

<form>
  <select name="countries">
    <option value="">Please select a Country</option>
    <option value="arg">Argentina</option>
    <option value="bra">Brasil</option>
    <option value="chl">Chile</option>
    <option value="can" selected>Canada</option>
  </select>
</form>

The multiple attribute will allow the user to select multiple options
The size attribute configures the number o items we'll show at the same time
To select many items we'll use the control key

Example

<form>
  <select name="countries" multiple="multiple" size="4">
    <option value="">Please select a Country</option>
    <option value="arg">Argentina</option>
    <option value="bra">Brasil</option>
    <option value="chl">Chile</option>
    <option value="can" selected>Canada</option>
  </select>
</form>

Buttons

The button element represents a clickable button, which can be used in forms, or anywhere in a document that needs simple, standard button functionality
To set the button content we need to use an opening and close tags
Add the value attribute if you need to submit this element value
MDN button doc

Example

<form>
  <button value="create" name="create-user">+ User</button>
</form>

We can add any html content like an image

Example

<form>
  <button>
    <img src="plus-icon.png" alt="plus icon" />
    User
  </button>
</form>

File

The file input type is a control that lets the user select a file
Use the accept attribute to define the types of files that the control can select
As we're going to be submitting more than just text we need to change the form enctype to enctype="multipart/form-data" and use the post method
By default we can only select one file
Use the multiple attribute indicates whether the user can enter more than one value (only HTML5 and all browsers might not support it)
MDN input type file doc

Example

<form action="upload.php" method="post" enctype="multipart/form-data">
  <input type="file" name="filename" />
  <input type="file" name="filename" multiple="multiple" />
  <input type="file" name="filename" multiple />
</form>

Practice

Exercise 13

New HTML5 input types

HTML5 adds some new specific inputs
If the browser doesn't support them it will show an input type text element
HTML5 forms input types
See them in action

Date

The input type date is a control for entering a date (year, month, and day, with no time)
We can set a initial value using the value attribute
MDN input type date doc

Example

<form>
  <input type="date" name="birthday" />
  <input id="date" type="date" value="1980-04-02" />
</form>

Email

The input type email is a field for editing an e-mail address
MDN input type email doc

Example

<form>
  <input type="email" name="email" />
</form>

URL

The input type url is a field for entering a URL
MDN input type url doc

Example

<form>
  <input type="url" name="personalsite" />
</form>

Search

The input type search is a single-line text field for entering search strings
Line-breaks are automatically removed from the input value

Example

<form>
  <input type="search" name="query" />
</form>

Practice

Exercise 14

Form validation

To make sure that the data users fill out in forms is in the correct format we need to process the form inputs
We can validate on client and server side
We'll use some HTML elements attribute to validate our forms on the client side
If we validate on the client side we avoid sending wrong data to the server so we have many requests
HTML5 added element validations
Also we can use JavaScript to validate our inputs too

Required

The required attribute specifies that the user must fill in a value before submitting a form
As it's a boolean attribute we can just write the attribute name without any value (required="required" or just required)
The form won't submit until all required inputs are completed

Example

<form>
  <input type="text" name="name" required />
  <input type="text" name="name" required="required" />
</form>

Regex

A regular expressions is a pattern used to match character combinations in strings
We can use them in many different languages
The attribute pattern allows us to enter a valid regex as value
This regular expression will be executed with the input value to see if it match
The pattern must match the entire value
This attribute applies when the value of the type attribute is text, search, tel, url, email, or password, otherwise it is ignored
The regular expression language is the same as JavaScript RegExp algorithm
The pattern is not surrounded by forward slashes
It's a good practice to add the title attribute to explain the allowed values
Add the placeholder if you use this attribute or it might not show the title content
Wikipedia - Regular_expression
Nice regex tutorial

Example

<form>
  <input
    type="text"
    name="name"
    pattern="^[a-zA-Z]+$"
    placeholder="name"
    title="Input only letters"
  />
  <input
    type="text"
    name="age"
    pattern="\d+"
    placeholder="age"
    title="Input only numbers"
  />
  <input type="submit" value="Submit" />
</form>

Use caniuse.com to find out if a feature is compatible with the browser you're targeting
To know more about this subject you can read the MDN form validation guide

HTML5 new sections

HTML5 specification brings several new elements to web developers allowing them to describe the structure of a web document with standard semantics
All content lying inside the body element is part of a section
Sections in HTML5 can be nested
Each section can have its own heading hierarchy. Therefore, even a nested section can have an h1
HTML5 adds the following features:
- Semantics: allowing you to describe more precisely what your content is
- Connectivity: allowing you to communicate with the server in new and innovative ways
- Offline and storage: allowing webpages to store data on the client-side locally and operate offline more efficiently
- Multimedia: making video and audio first-class citizens in the Open Web
- 2D/3D graphics and effects: allowing a much more diverse range of presentation options
- Performance and integration: providing greater speed optimization and better usage of computer hardware
- Device access: allowing for the usage of various input and output devices
- Styling: letting authors write more sophisticated themes
MDN HTML5 guide
In the semantics section we find new outlining and sectioning elements like section, article, nav, header, footer and aside.
The header element represents introductory content, typically a group of introductory or navigational aids
It may contain some heading elements but also other elements like a logo, a search form, an author name, and so on
The nav element represents a section of a page whose purpose is to provide navigation links, either within the current document or to other documents
The aside element represents a portion of a document whose content is only indirectly related to the document's main content
The section element represents a standalone section — which doesn't have a more specific semantic element to represent it — contained within an HTML document
The footer element represents a footer for its nearest sectioning content or sectioning root element
A footer typically contains information about the author of the section, copyright data or links to related documents

Example

<body>
  <header>
    <h1>Title of our document</h1>
  </header>
  <nav>
    <ul>
      <li><a href="/">Home</a></li>
      <li><a href="bio.html">Bio</a></li>
    </ul>
  </nav>
  <aside>
    <p>Aside Content</p>
  </aside>
  <section>
    <h1>Section Main Title</h1>
    <p>Section Content</p>
  </section>
  <footer>
    <p>Site Footer</p>
  </footer>
</body>

The *article element represents a self-contained composition in a document, page, application, or site, which is intended to be independently distributable or reusable. Examples include: a forum post, a magazine or newspaper article, or a blog entry
The address element indicates that the enclosed HTML provides contact information for a person or people, or for an organization
The HTML time element represents one of the following: a time on a 24-hour clock or a precise date in the Gregorian calendar

Example

<body>
  <article>
    <p>Author Name</p>
    <time>02/02/2017</time>
    <address>
      136 Market Av.
    </address>
  </article>
</body>

Iframe

The iframe element represents a nested browsing context, effectively embedding another HTML page into the current page
The src attribute accepts the URL of the page to embed as value
Use the height & width attributes to set the iframe size
The seamless is a boolean attribute indicates that the browser should render the inline frame in a way that makes it appear to be part of the containing document
The frameborder attribute tells the browser to draw a border between this frame. If we set the value to 0 tells the browser not to draw a border between this frame
MDN iframe doc

Example

<body>
  <iframe
    src="other_document.html"
    height="200"
    width="200"
    seamless
    frameborder="0"
  ></iframe>
</body>

Practice

Exercise 15

Video

The video element embeds a media player which supports video playback into the document
This element contains one or more video sources
To specify a video source, use either the src attribute or the source element (the browser will choose the most suitable one)
Different browsers might support different media types
- H264: Internet Explorer & Safari
- WebM: Android, Chrome, Firefox and Opera
For a list of supported formats you can see the MDN supported media formats guide
Each browser will show the player in a different way
Also we can still use flash plugin to reach more users
This are some of the attributes that we can use to configure the video element
- src: set this value with the video filename or path
- width: & height: to set the video player size
- poster: we can set a picture file or path that will show while the video is downloaded
MDN video doc

Example

<body>
  <video src="myvideo.mp4" poster="myvideo.jpg" width="600" height="400">
    <p>Video description</p>
  </video>
</body>

The video element has many attributes that works as a boolean value to turn on/off the different features
- controls: if this attribute is present, the browser will offer controls to allow the user to control video playback, including volume, seeking, and pause/resume playback
- autoplay: if specified, the video automatically begins to play back as soon as it can do so without stopping to finish loading the data
- loop: upon reaching the end of the video the player automatically seek back to the start
- preload: This enumerated attribute is intended to provide a hint to the browser about what the author thinks will lead to the best user experience.
  - It may have one of the following values:
    - none: indicates that the video should not be preloaded
    - auto: indicates that the whole video file could be downloaded, even if the user is not expected to use it
    - metadata: indicates that only video metadata (e.g. length) is fetched
    - An empty string: synonym of the auto values

Example

<body>
  <video
    src="myvideo.mp4"
    poster="myvideo.jpg"
    width="600"
    height="400"
    controls
  >
    <p>Video Description</p>
  </video>
</body>

Audio

The audio element is used to embed sound content in documents
It may contain one or more audio sources, represented using the src attribute or the source element: the browser will choose the most suitable one
It can also be the destination for streamed media, using a MediaStream
This element works in a similar way as the video one
The audio element supports the same attribute video does: src, controls, autoplay, preload & loop
Some browsers have better support for some media types:
- MP3: Safari 5+, Chrome 6+ e IE9
- Ogg Vorbis: Firefox 3.6, Chrome 6, Opera 1.5 e IE9
Also if the browser doesn't support this tag it will render the element content (like the paragraph in the example)
MDN audio doc
MDN media stream doc

Example

<body>
  <audio src="ejemplo-audio.ogg" autoplay controls>
    <p>Audio description.</p>
  </audio>
</body>

Source

The source element specifies multiple media resources for the picture, audio and video elements
It is an empty element
It is commonly used to serve the same media content in multiple formats supported by different browsers
If we use this element we don't have to use the src attribute
This element supports the following attributes:
- src: required for audio and video, address of the media resource
  - The value of this attribute is ignored when the source element is placed inside a picture element
- type: the MIME-type of the resource, optionally with a codecs parameter
  - See RFC 4281 guide for information about how to specify codecs
MDN source doc
MDN picture doc

Example

<body>
  <video poster="myvideo.jpg" controls>
    <source src="myvideoo.mp4" type="video/mp4" />
    <source src="myvideo.webm" type="video/webm" />
    <source src="myvideo.ogv" type="video/ogg" />
    <source src="myvideo.3gp" type="video/3gp" />
    <p>Vide description</p>
  </video>
  <audio autoplay controls>
    <source src="myaudio.mp3" />
    <source src="myaudio.ogg" />
    <p>Audio description.</p>
  </audio>
</body>

Metadata

The meta element represents metadata that cannot be represented by other HTML meta-related elements
This element will work as head element content only
The user won't see this element content
This are some of the attributes that we can configure:
- author: author which defines the name of the document's author
- charset: this attribute declares the page's character encoding
- description: contains a short and accurate summary of the content of the page
- keywords: contains words relevant to the page's content separated by commas
- viewport: gives hints about the size of the initial size of the viewport
  - Used by mobile devices only
  - Read the viewport MDN guide section to find out more about the different values this attribute supports
Read the MDN meta doc too know more about the different attributes that we can use

Example

<head>
  <meta charset="UTF-8" />
  <meta name="description" content="My Site description" />
  <meta name="author" content="John Doe" />
  <meta name="keywords" content="HTML,CSS,XML,JavaScript" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
</head>

Read the Wikipedia character encoding doc to know more about how encoding works
Wikipedia UTF-8 doc

HTML Entity

An HTML entity is a piece of text ("string") that begins with an ampersand (&) and ends with a semicolon (;)
Entities are frequently used to display reserved characters (which would otherwise be interpreted as HTML code), and invisible characters (like non-breaking spaces)
You can also use them in place of other characters that are difficult to type with a standard keyboard MDN entity doc
List of HTML entities

Example

<body>
  <p>&lt; less than</p>
  <p>&gt; greater than</p>
  <p>&amp; ampersand</p>
  <p>&copy; Copyright</p>
  <p>&reg; Registered Trademark</p>
  <p>&trade; Trademark</p>
</body>

Practice

Exercise 16

Exercise 17

Extra:

HTML5 Specs

Congratulations, you made it, now you know HTML!!

Super Hero HTML5

What is HTML?​

Tag Structure​

Tag attribute​

Tag with tags!​

HTML Tags​

HTML document structure​

HTML5 Doctype​

HTML​

HEAD​

Title​

BODY​

Basic HTML file​

Practice​

Heading Elements​

Paragraph​

Practice​

Containers​

Div​

Span​

Inline vs Block elements​

Comments​

Line Break​

Horizontal Rule​

Practice​

Text Format​

Lists​

Unordered list​

Ordered list​

Description or definition list​

Nested list​

Practice​

Hyperlink​

External links​

Target attribute​

Absolute & relative URLs​

Mailto​

Anchor​

Practice​

Images​

Figure & Figure caption​

Practice​

Table​

Practice​

Practice​

Make the tables happier!​

Practice​

Favicon​

Practice​

Forms​

Inputs​

Text​

Password​

Submit button​

Practice​

Labels​

Fieldset​

Radio buttons​

Checkboxes​

Hidden​

Image buttons​

Practice​

Text area​

Select​

Buttons​

File​

Practice​

New HTML5 input types​

Date​

Email​

URL​

Search​

Practice​

Form validation​

Required​

Regex​

HTML5 new sections​

Iframe​

Practice​

Video​

Audio​

What is HTML?

Tag Structure

Tag attribute

Tag with tags!

HTML Tags

HTML document structure

HTML5 Doctype

HTML

HEAD

Title

BODY

Basic HTML file

Practice

Heading Elements

Paragraph

Practice

Containers

Div

Span

Inline vs Block elements

Comments

Line Break

Horizontal Rule

Practice

Text Format

Lists

Unordered list

Ordered list

Description or definition list

Nested list

Practice

Hyperlink

External links

Target attribute

Absolute & relative URLs

Mailto

Anchor

Practice

Images

Figure & Figure caption

Practice

Table

Practice

Practice

Make the tables happier!

Practice

Favicon

Practice

Forms

Inputs

Text

Password

Submit button

Practice

Labels

Fieldset

Radio buttons

Checkboxes

Hidden

Image buttons

Practice

Text area

Select

Buttons

File

Practice

New HTML5 input types

Date

Email

URL

Search

Practice

Form validation

Required

Regex

HTML5 new sections

Iframe

Practice

Video

Audio