:first-of-type Selector

first-of-type ( ) version added: 1.9

Description: Selects all elements that are the first among siblings of the same element name.

The :first-of-type selector matches elements that have no other element with both the same parent and the same element name coming before it in the document tree.

Examples:

Example: Find the first span in each matched div and add a class to it. 

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

  <style>

  span.fot {
    color: red;
    font-size: 120%;
    font-style: italic;
  }

  </style>

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

<div>
  <span>Corey,</span>
  <span>Yehuda,</span>
  <span>Adam,</span>
  <span>Todd</span>
</div>
<div>
  <b>Nobody,</b>
  <span>Jörn,</span>
  <span>Scott,</span>
  <span>Timo</span>
</div>

<script>

$( "span:first-of-type" ).addClass( "fot" );

</script>

  
</body>
</html>

Demo: