JavaScript Tutorial

has()

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>has demo</title>
  <style>
  .full {
    border: 1px solid red;
  }
  </style>
  <script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
<ul><li>Does the UL contain an LI?</li></ul>
<script>
$( "ul" ).append( "<li>" +
  ( $( "ul" ).has( "li" ).length ? "Yes" : "No" ) +
  "</li>" );
$( "ul" ).has( "li" ).addClass( "full" );
</script>
</body>
</html>