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

Browser compatibility