CSS terminology: what are these called?

问题

Consider:

p {
  ...
}

.foo {
  ...
}

#bar {
  ...
}

What is the correct name for these statements in CSS? I've seen them called selectors, rules or rulesets, but which is correct?

回答1:

A rule would be considered:

p {…}

A selector in this case is:

p

A rule is made up of selectors and declarations. A declaration is property:value so the entire rule would be:

selector { property:value }

A rule can have multiple declarations and multiple selectors so we can actually have:

selector, selector2
{
  property:value;
  property2:value;
}

A rule set would be multiple rules.

Here's a quick source on this or the CSS 1 Specification.

回答2:

CSS is made up of a number of rules in the form

selector{declaration}

So the .foo and #bar and p are called selectors but the full statement with the curlies are called rules.

回答3:

They are selectors - see W3C specification

回答4:

According to the specification, they are called Selectors.

回答5:

In this example:

p.class, #id > a {
foo:bar;
}

p, #id > a is group of selectors. p.class and #id are selectors. Selectors are built from simple selectors and combinators: p is a type selector, .class is a class selector (not a class). Combinators are '+', '>', '', etc.

selectors {...} is a rule. It's a mistake to call it class.

foo:bar is a declaration for foo property.

http://www.w3.org/TR/CSS2/grammar.html

回答6:

I usually call them rules or classes.

来源：https://stackoverflow.com/questions/1120264/css-terminology-what-are-these-called

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terminology