:first-child Selector

first-child ( ) version added: 1.1.4

Description: Selects all elements that are the first child of their parent.

While :first matches only a single element, the :first-child selector can match more than one: one for each parent. This is equivalent to :nth-child(1).

Examples:

Example: Finds the first span in each matched div to underline and add a hover state. 

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>css demo</title>

  <style>

  span {
    color: #008;
  }
  span.sogreen {
    color: green;
    font-weight: bolder;
  }

  </style>

  <script src="//code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
  

<div>
  <span>John,</span>
  <span>Karl,</span>
  <span>Brandon</span>
</div>
<div>
  <span>Glen,</span>
  <span>Tane,</span>
  <span>Ralph</span>
</div>

<script>

$( "div span:first-child" )
  .css( "text-decoration", "underline" )
  .hover(function() {
    $( this ).addClass( "sogreen" );
  }, function() {
    $( this ).removeClass( "sogreen" );
  });

</script>

  
</body>
</html>

Demo: