<html>
<head>
<script src="https://libs.baidu.com/jquery/1.10.2/jquery.min.js">
</script>
<script>
$(document).ready(function(){
$("p").filter(function(){
return $("span",this).length==2;}).css("background-color","yellow");
});
</script>
</head>
<body>
<div>
<p>A p element <span>with one span element.</span></p>
<p>A p element <span>with</span> two <span>span elements.</span></p>
<p>A p element <span>with one span element.</span></p>
<p>A p element <span>with</span> two <span>span elements.</span></p>
<p>A p element with no span element.</p>
</div>
<p>This example returns all p elements that have two span elements. P elements with none, one, or more than two span elements, will not be returned.</p>
</body>
</html>