JavaScript实现文本框中默认显示背景图片在获得焦点后消失的方法

<form name="searchform" id="search-form">  <div>    <b>Search</b>    <input type="text" name="txtInput"     title="Enter the terms you wish to search for." />    <input type="submit" value="GO!" class="submit"    style="cursor: pointer;" />  </div></form>

<script type="text/javascript" language="javascript"> (function() {  var id = document.getElementById('search-form');  if (id && id.txtInput) {   var name = id.txtInput;   var unclicked = function() {     if (name.value == '') {       name.style.background = '#FFFFFF url(images/googbg.png) left no-repeat';     }    };    var clicked = function() {     name.style.background = '#ffffff';    };  name.onfocus = clicked;  name.onblur = unclicked;  unclicked();  } })();</script>