Specifies the unique id attribute of the html element-HTML Tutorial-php.cn

Specifies the unique id attribute of the html element

黄舟

Release： 2017-11-03 11:49:30

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Example

Use the id attribute to change a piece of text through JavaScript:

<html>
<head>
<script type="text/javascript">
function change_header()
{
document.getElementById("myHeader").innerHTML="Nice day!";
}
</script>
</head>

<body>
<h1 id="myHeader">Hello World!</h1>
<button onclick="change_header()">Change text</button>
</body>

</html>
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Definition and usage

id attribute Specifies the unique id of the HTML element.

id must be unique within the HTML document.

The id attribute can be used as a link anchor to change or add styles to an element with a specified id via JavaScript (HTML DOM) or via CSS.

Support

W3C: The "W3C" column indicates whether the attribute is defined in the W3C's HTML/XHTML recommendations.

IE	Firefox	Opera	Safari	W3C
YES	YES	YES	YES	YES

Syntax

<element id="value">

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Value	Description
id	Specifies the unique id of the element.

There may be several reasons for using the id attribute

You want to link to a specified location on a page
You want to use a specific css style on a certain HTML element
You want to use script for each HTML element (such as javascript)
You want to differentiate between two identical HTML elements

Example

<div id="dreamdu1">使用dreamdu1和dreamdu2来区分两个div标签<div><div id="dreamdu2">使用dreamdu1和dreamdu2来区分两个div标签<div>

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Instructions

The same attribute as the id attribute is name. This attribute can be used in HTML4 documents. The new web standard has abandoned this attribute. Therefore, when using the name attribute, you should use the XHTML transition definition type (xhtml1- transitional.dtd), cannot be used in XHTML strictly defined types (xhtml1-strict.dtd)
The id attribute must be unique in the entire page and CSS style sheet, and in the entire website The best and only

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