ID selectors

In an HTML document, CSS ID selectors match an element based on the contents of that element's id attribute, which must match exactly the value given in the selector.

Syntax

#id_value { style properties }

Note this is equivalent to the following attribute selector:

[id=id_value] { style properties }

Example

span#identified {
  background-color: DodgerBlue;
}

<span id="identified">Here's a span with some text.</span>
<span>Here's another.</span>

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