Universal Selector (CSS Selector)

May 14, 2014

Description

The universal selector matches any element type. It can be implied (and therefore omitted) if it isn’t the only component of the simple selector. The two selector examples shown here are equivalent:

*.warning {
  ⋮ declarations
}
.warning {
  ⋮ declarations
}

It’s important not to confuse the universal selector with a wildcard character—the universal selector doesn’t match “zero or more elements.” Consider the following HTML fragment:

<body>
  <div>
    <h1>The <em>Universal</em> Selector</h1>
    <p>We must <em>emphasize</em> the following:</p>
    <ul>
      <li>It's <em>not</em> a wildcard.</li>
      <li>It matches elements regardless of <em>type</em>.</li>
    </ul>
    This is an <em>immediate</em> child of the division.
  </div>
</body>

The selector div * em will match the following em elements:

“Universal” in the h1 element (* matches the <h1>)
“emphasize” in the p element (* matches the <p>)
“not” in the first li element (* matches the <ul> or the <li>)
“type” in the second li element (* matches the <ul> or the <li>)

However, it won’t match the <em>immediate</em> element, since that’s an immediate child of the div element—there’s nothing between <div> and <em> for the * to match.

Example

This rule set will be applied to every element in a document:

* {
  margin: 0;
  padding: 0;
}