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5

HTML Attributes

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Gli attributi forniscono ulteriori informazioni sugli elementi HTML.

HTML Attributes

  • 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 tag. The link address is specified in the href attribute:

 

Example

This is a link

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

 


The src Attribute

HTML images are defined with the tag.

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

Example


The width and height Attributes

 HTML images also have width and height attributes, which specifies the width and height of the image:

Example

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

The alt attribute specifies an alternative text to be used, if an 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.

Example

Girl with a jacket

The alt attribute is also useful if the image cannot be displayed (e.g. if it does not exist):

Example

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

Girl with a jacket



The style Attribute

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

Example

 

This is a paragraph.

 

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

tag.

The language is declared with the lang attribute.

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

Here, a title attribute is added to the

element. The value of the title attribute will be displayed as a tooltip when you mouse over the paragraph:

Example

 


This is a paragraph.

 


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.

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 HTML5 standard does not require quotes around attribute values.

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

Bad

 

Good

 

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:

Example

 

 

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:

 

 


Chapter Summary


HTML Exercises

Test Yourself With Exercises

Exercise:

Add a "tooltip" to the paragraph below with the text "About W3Schools".

 

W3Schools is a web developer's site.

 

 

Start the Exercise


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
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

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  • 2020-04-11 18:39:29
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