An HTML attribute provides additional information about an HTML element.
- 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 href Attribute
HTML links are defined with the
<a> tag. The link address is specified in the
You will learn more about links and the
<a> tag later in this tutorial.
The src Attribute
HTML images are defined with the
The filename of the image source is specified in the
The width and height Attributes
HTML images also have
height attributes, which specifies the width and
height of the image:
The width and height are specified in pixels by default; so width="500" means 500 pixels wide.
You will learn more about images in our HTML Images chapter.
The alt Attribute
alt attribute specifies an alternative text to be used,
image cannot be displayed.
The value of the
alt attribute can be read by screen readers. This way, someone "listening"
to the webpage, e.g. a vision impaired person, can "hear" the element.
alt attribute is also useful if the image
cannot be displayed (e.g. if it does not exist):
See what happens if we try to display an image that does not exist:
The style Attribute
style attribute is used to specify the styling of an element, like color,
font, size etc.
You will learn more about styling later in this tutorial, and in our CSS Tutorial.
The lang Attribute
The language of the document can be declared in the
The language is declared with the
Declaring a language is important for accessibility applications (screen readers) and search engines:
The first two letters specify the language (en). If there is a dialect, add two more letters (US).
The title Attribute
title attribute is added to the
The value of the title attribute will be displayed as a tooltip when
you mouse over the paragraph:
This is a paragraph.
We Suggest: Use Lowercase Attributes
The HTML standard does not require lowercase attribute names.
The title attribute can be written with uppercase or lowercase like title or TITLE.
W3C recommends lowercase in HTML, and demands lowercase for stricter document types like XHTML.
At W3Schools we always use lowercase attribute names.
We Suggest: Quote Attribute Values
The HTML standard does not require quotes around attribute values.
href attribute can be written without quotes:
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:
Using quotes are the most common. Omitting quotes can produce errors.
At W3Schools 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:
Or vice versa:
- All HTML elements can have attributes
titleattribute provides additional "tool-tip" information
hrefattribute provides address information for links
heightattributes provide size information for images
altattribute provides text for screen readers
- At W3Schools we always use lowercase attribute names
- At W3Schools we always quote attribute values
Below is an alphabetical list of some attributes often used in HTML, which you will learn more about in this tutorial:
|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)|
A complete list of all attributes for each HTML element, is listed in our: HTML Attribute Reference.