CSS comments use // syntax, 1. Only // can wrap the annotation content, and support single-line and multi-line comments; 2. Comments are used to mark style blocks, interpret complex code, or temporarily disable styles; 3. Comments cannot be nested, nor do they support comments in form //. Only // is valid in standard CSS, and comments will not affect style rendering, which ensures that the code is clear and maintainable.
To comment in CSS, you use the /* */
syntax. Unlike HTML or JavaScript, CSS only has one way to add comments.

Basic CSS Comment Syntax
Wrap your comment text inside /*
and */
like this:
/* This is a single-line comment */ p { color: blue; } /* This is a multi-line comment */ h1 { font-size: 24px; }
These comments are ignored by browsers and won't affect how your styles are applied.

Why Use Comments in CSS?
Comments help you (and others) understand your code later. Common uses include:
Section headings : Label different parts of your stylesheet.
/* Header Styles */ header { background: #333; color: white; } /* Footer Styles */ footer { padding: 20px; text-align: center; }
Explaining tricky code : Clarify why a certain rule exists.
.box { position: relative; z-index: 1; /* Needed to keep box above the floating banner */ }
Temporarily disabling styles :
.button { /* background-color: red; */ background-color: blue; }
This is great for testing without deleting code.
Things to Avoid
You can't nest comments:
/* /* This will break */ */
The comment ends at the first
*/
, so the rest becomes invalid.No
//
comments (that's for JavaScript or preprocessors like Sass):// This won't work in plain CSS p { color: green; }
Note: Preprocessors like Sass or Less support
//
for single-line comments, but standard CSS does not.So stick with
/* */
— it works everywhere in regular CSS.Basically, just wrap anything you want hidden from the browser in
/* */
, and use it to keep your styles organized and clear.The above is the detailed content of How to comment in CSS?. For more information, please follow other related articles on the PHP Chinese website!

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