CSS id selectors

Last update on August 19 2022 21:50:52 (UTC/GMT +8 hours)

Id selectors

CSS id selectors select any element in an HTML page, if it has an attribute called id, whose value matches the name of the id selector.

In a stylesheet document, the name of the id selector is preceded by a "#".

If an id selector is combined with another or more selectors, id selectors must be preceded with a #.

IDs can only be applied once in an HTML page.

syntax:

#idname{ CSS-Property: value; ........................ }

Simple Example of CSS id selectors

CSS code:

 #w3r {
color: red; /* sets color to red */ 
background-color: aliceblue; /* sets background color to aliceblue */ 
}

HTML code:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>Simple Example of CSS id selectors</title>
<link rel='stylesheet' href='Simple-Example-of-CSS-id-selector.css' type='text/css'>
</head>
<body>
<p id="w3r" >Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a urna elit.</p>
</body>
</html>

Result:

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a urna elit.

View this simple example of CSS id selector in a separate browser window.

Advanced Example of CSS id selectors

CSS code:

p#w3r {
color: red; /* sets color to red */
background-color: aliceblue; /* sets background color to aliceblue */
}
h2#w3r {
color: blue; /* sets color to blue */
background-color: lime; /* sets background color to lime */
}

HTML code:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>Advanced Example of CSS id selectors</title>
<link rel='stylesheet' href='Advanced-Example-of-CSS-id-selector.css' type='text/css'>
</head>
<body>
<div>
<h2 id="w3r">CSS examples</h2>
<p id="w3r">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a urna elit.</p>
</div>
</body>
</html>

Result:

CSS examples:

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a urna elit.

View this advanced example of CSS id selector in a separate browser window.

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