Tag Attributes

Tag Attributes in HTML

HTML Attributes

Attributes provide additional information about HTML elements.

  • All HTML elements can have attributes
  • Attributes provide additional information about an element
  • Attributes are always specified in the start tag
  • Attributes usually come in name/value pairs like: name="value"

The lang Attribute

  • The language of the document can be declared in the <html> tag.
  • The language is declared with the lang attribute.
  • Declaring a language is important for accessibility applications (screen readers) and search engines:

Example

<!DOCTYPE html>
<html lang="en-US">
<body>
               ...
</body>
</html>

The first two letters specify the language (en). If there is a dialect, use two more letters (US).


The title Attribute

Here, a title attribute is added to the <p> element. The value of the title attribute will be displayed as a tooltip when you mouse over the paragraph :

Example

<!DOCTYPE html>
<html>
<body>

<h2>The title attribute</h2>

<p title="I'm a tooltip">
Mouse over this paragraph, to display the title attribute as a tooltip.
</p>

</body>
</html>

Click here to Run the Program

The href Attribute

HTML links are defined with the <a> tag. The link address is specified in the href attribute :

Example

<a href="http://www.w3professors.com">W3Professors This is a link</a>
Click here to Run the Program

You will learn more about links and the <a> tag later in this tutorial.


Size Attributes

HTML images are defined with the <img> tag.

The filename of the source (src), and the size of the image (width and height) are all provided as attributes:

Example

  <img src="w3schools.jpg" width="104" height="142"> 

The image size is specified in pixels: width="104" means 104 screen pixels wide.

You will learn more about images and the <img> tag later in this tutorial.


The alt Attribute

The alt attribute specifies an alternative text to be used, when an image cannot be displayed.

The value of the attribute can be read by screen readers. This way, someone "listening" to the webpage, e.g. a blind person, can "hear" the element.

Example

<img src="w3professors.png" alt="W3professors.com" width="104" height="142"> 
Click here to Run the Program

We Suggest : Use Lowercase Attributes

  • The HTML5 standard does not require lowercase attribute names.
  • The title attribute can be written with uppercase or lowercase like Title and/or TITLE.
  • W3C recommends lowercase in HTML, and demands lowercase for stricter document types like XHTML.
  • we always use lowercase attribute names. - W3Professors

We Suggest : Quote Attribute Values

  • The HTML5 standard does not require quotes around attribute values.
  • The href attribute, demonstrated above, can be written as :
 <a href=http://www.w3professors.com>W3professors</a>
Click here to Run the Program

W3C recommends quotes in HTML, and demands quotes for stricter document types like XHTML.

Sometimes it is necessary to use quotes. This example will not display the title attribute correctly, because it contains a space:

 <p title=About W3Professors>
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Using quotes are the most common. Omitting quotes can produce errors. At W3Professors we always use quotes around attribute values.

Single or Double Quotes?

Double quotes around attribute values are the most common in HTML, but single quotes can also be used.

In some situations, when the attribute value itself contains double quotes, it is necessary to use single quotes :

<p title='John "ShotGun" Nelson'>
Or vice versa :
<p title="John 'ShotGun' Nelson">

Chapter Summary

  • All HTML elements can have attributes
  • The title attribute provides additional "tool-tip" information
  • The href attribute provides address information for links
  • The width and height attributes provide size information for images
  • The alt attribute provides text for screen readers
  • At W3Professors we always use lowercase attribute names
  • At W3Professors we always quote attribute values with double quotes

HTML Attributes

Below is an alphabetical list of some attributes often used in HTML:

Attribute Description
alt Specifies an alternative text for an image, when the image cannot be displayed
disabled Specifies that an input element should be disabled
href Specifies the URL (web address) for a link
id Specifies a unique id for an element
src Specifies the URL (web address) for an image
style Specifies an inline CSS style for an element
title Specifies extra information about an element (displayed as a tool tip)