ID selectors

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

Browser compatibility