HTML id
Attribute
Example
Using the id
attribute with JavaScript to manipulate a piece of text:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>tutorialpro.org(tutorialpro.org)</title>
<script>
function displayResult()
{
document.getElementById("myHeader").innerHTML="Have a nice day!";
}
</script>
</head>
<body>
<h1 id="myHeader">Hello World!</h1>
<button onclick="displayResult()">Edit Text</button>
</body>
</html>
Browser Support
All major browsers support the id
attribute.
Definition and Usage
The id
attribute specifies a unique id for an HTML element.
The value of the id
must be unique within the HTML document.
The id
attribute can be used as a link anchor, and to style or manipulate elements with the specified id using JavaScript (HTML DOM) or CSS.
Differences Between HTML 4.01 and HTML5
In HTML5, the id
attribute can be used on any HTML element (it will validate any HTML element, though not necessarily be useful).
In HTML 4.01, the id
attribute cannot be used with:
<base>
, <head>
, <html>
, <meta>
, <param>
, <script>
, <style>
, and <title>
.
Note: HTML 4.01 had strict restrictions on the value of id
(e.g., in HTML 4.01, the id value cannot start with a digit).
Syntax
Attribute Values
Value | Description |
---|---|
id | Specifies a unique id for the element. Naming rules: Must start with a letter A-Z or a-z<br>Subsequent characters: Letters (A-Za-z), digits (0-9), hyphens ("-"), underscores ("_"), colons (":"), and periods (".")<br>The value is case-sensitive |
| | More Examples |