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/CSS

ID selectors

The CSS ID selector matches an element based on the value of the element's id attribute. In order for the element to be selected, its 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 syntactically (but not specificity-wise), this is equivalent to the following attribute selector:

[id=id_value] { style properties }

Examples

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
Selectors Level 4 # id-selectors

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`ID_selectors`	1	12	1	3	3.5	1	≤37	18	4	10.1	1	1.0