How Does the Ampersand (&) Work in CSS Nested Selectors?

Nested Selectors in CSS: An Ampersand (&) Uncovered

In the realm of CSS, the ampersand (&) symbol plays a significant role when utilized with pseudo-elements. Developers encounter this syntax in libraries such as Twitter Bootstrap, but its true nature isn't immediately apparent.

What the Ampersand Does

In the example provided from Twitter Bootstrap, the ampersand (&) is used with the pseudo-elements :before and :after. This syntax allows for the nesting of selector modifiers.

LESS Syntax, Not CSS

It's important to note that the syntax in question is not a part of CSS but belongs to LESS, a preprocessor that extends CSS. LESS simplifies the development process by providing additional features and functionalities.

Example Usage and Compilation

The following example illustrates how the ampersand (&) functions:

.clearfix {
  & :before {
    content: '';
  }
}

This code will compile to:

.clearfix:before {
  content: '';
}

Without the ampersand (&), the code would compile to:

.clearfix :before {
  content: '';
}

By using the ampersand (&), the nested selector compiles to .clearfix:before, while without it, it compiles to .clearfix :before. This distinction is crucial for correct styling.

The above is the detailed content of How Does the Ampersand (&) Work in CSS Nested Selectors?. For more information, please follow other related articles on the PHP Chinese website!