Руководство jQuery - jQuery.removeData(elem)

    var adiv = $("div").get(0);
    $("span:eq(0)").text("" + jQuery.data(adiv, "test1"));
    jQuery.data(adiv, "test1", "VALUE-1");
    jQuery.data(adiv, "test2", "VALUE-2");
    $("span:eq(1)").text("" + jQuery.data(adiv, "test1"));
    jQuery.removeData(adiv);
    $("span:eq(2)").text("" + jQuery.data(adiv, "test1"));
    $("span:eq(3)").text("" + jQuery.data(adiv, "test2"));

"HTML"

<div>value1 before creation: <span></span></div>
  <div>value1 after creation: <span></span></div>
  <div>value1 after removal: <span></span></div>
  <div>value2 after removal: <span></span></div>

"CSS"

  div { margin:2px; color:blue; }
  span { color:red; }

"Живой пример jQuery"

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 
						"http://www.w3.org/TR/html4/loose.dtd">
	<html>
	<head>
	<link href="http://test-drupal.ru/themes/slyweb/css/jqueryiframe.css" 
	rel="stylesheet" type="text/css"/>
	  <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.5.0/jquery.min.js"></script>
	<script>
	  $(document).ready(function(){
	
    var adiv = $("div").get(0);
    $("span:eq(0)").text("" + jQuery.data(adiv, "test1"));
    jQuery.data(adiv, "test1", "VALUE-1");
    jQuery.data(adiv, "test2", "VALUE-2");
    $("span:eq(1)").text("" + jQuery.data(adiv, "test1"));
    jQuery.removeData(adiv);
    $("span:eq(2)").text("" + jQuery.data(adiv, "test1"));
    $("span:eq(3)").text("" + jQuery.data(adiv, "test2"));

	  });
	</script>

	</head>
	<body class="iframe">

	
<div>value1 before creation: <span></span></div>
  <div>value1 after creation: <span></span></div>
  <div>value1 after removal: <span></span></div>
  <div>value2 after removal: <span></span></div>


	</body>
	</html>

	
	<style>
	
  div { margin:2px; color:blue; }
  span { color:red; }
 
	</style>

Метод появился в jQuery 1.2 (http://api.jquery.com/jQuery.removeData/)

Версия jQuery 1.4.2 Документ создан 2010-08-21