In an HTML document, the CSS ID selector matches an element based on the value of its id attribute. The selected element's ID attribute must match exactly the value given in the selector.

/* The element with id="demo" */
#demo {
  border: red 2px solid;
}

Syntax

#id_value { style properties }

Note that this is equivalent to the following attribute selector:

[id=id_value] { style properties }

Example

CSS

#identified {
  background-color: skyblue;
}

HTML

<div id="identified">This div has a special ID on it!</div>
<div>This is just a regular div.</div>

Result

Specifications

Specification Status Comment
Selectors Level 4
The definition of 'ID selectors' in that specification.
Working Draft  
Selectors Level 3
The definition of 'ID selectors' in that specification.
Recommendation  
CSS Level 2 (Revision 1)
The definition of 'ID selectors' in that specification.
Recommendation  
CSS Level 1
The definition of 'ID selectors' in that specification.
Recommendation Initial definition

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support1121 Yes Yes Yes
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic support Yes Yes Yes4 Yes Yes Yes

Document Tags and Contributors

 Last updated by: WillBeethoven,