What Is a CSS Selector?

CSS stylesheet on a computer screen

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CSS relies on pattern matching rules to determine which style applies to which element in the document. These patterns are called selectors and they range from tag names (for example,

to match paragraph tags) to very complicated patterns that match very specific parts of a document. For example,
p#myid > b.highlight
would match any
tag with a class of
that is a child of the paragraph with the id
A CSS selector is the part of a CSS style call that identifies what part of the web page should be styled. The selector contains one or more properties that define how the selected HTML

The CSS Selectors

There are several different types of selectors:

Format CSS Styles and CSS Selectors

The format of a CSS style looks like this:

selector { style property : style ; }

Separate multiple selectors that have the same style with commas. This is called selector grouping. For example:

selector1, selector2 { style property : style ; }

Grouping selectors is a shorthand mechanism to keep your CSS styles compact. The above grouping would have the same effect as:

selector1 { style property : style ; }
selector2 { style property : style ; }

Always Test Your CSS Selectors

Not all older browsers support all the CSS selectors. If you are setting up CSS for use with browsers as old as IE8 or older, be sure to test your selectors in as many browsers on as many operating systems as you think might be used to access your code. If you are using CSS1, CSS2, or CSS3 selectors for use with current browsers, you should be fine.

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Kyrnin, Jennifer. "What Is a CSS Selector?" ThoughtCo, Sep. 30, 2021, thoughtco.com/what-is-a-css-selector-3467058. Kyrnin, Jennifer. (2021, September 30). What Is a CSS Selector? Retrieved from https://www.thoughtco.com/what-is-a-css-selector-3467058 Kyrnin, Jennifer. "What Is a CSS Selector?" ThoughtCo. https://www.thoughtco.com/what-is-a-css-selector-3467058 (accessed June 10, 2023).