# Attributes

Domains:

## The href Attribute

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

<a href="https://www.w3schools.com">This is a link</a>


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

## The src Attribute

HTML images are defined with the <img> tag.

The filename of the image source is specified in the src attribute:

<img src="img_girl.jpg">


## The width and height Attributes

Images in HTML have a set of size attributes, which specifies the width and height of the image:

<img src="img_girl.jpg" width="500" height="600">


The image size is specified in pixels: width="500" means 500 pixels wide.

## 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 vision impaired person, can "hear" the element.

<img src="img_girl.jpg" alt="Girl with a jacket">


The alt attribute is also useful if the image does not exist:

See what happens if we try to display an image that does not exist:

	<img src="img_typo.jpg" alt="Girl with a jacket">

## The style Attribute

The style attribute is used to specify the styling of an element, like color, font, size etc.

<p style="color:red">I am a paragraph</p>


## 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:

<!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:

<p title="I'm a tooltip">
This is a paragraph.
</p>


## 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 or TITLE.

We recommends lowercase in HTML, and demands lowercase for stricter document types like XHTML.

## We Suggest: Quote Attribute Values

The HTML5 standard does not require quotes around attribute values.

The href attribute, demonstrated above, can be written without quotes:

 Bad    Good   

We 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 W3Schools>


Using quotes are the most common. Omitting quotes can produce errors. 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
• We always use lowercase attribute names
• We always quote attribute values with double quotes

## HTML Attributes

Below is an alphabetical list of some attributes often used in HTML, which you will learn more about in this tutorial:

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
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)

A complete list of all attributes for each HTML element, is listed in: HTML Attribute Reference.

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