xmlhttp有关问题:用JS怎么获取XML内指定的信息?

xmlhttp问题:用JS如何获取XML内指定的信息??急.
<!DOCTYPE   html   PUBLIC   "-//W3C//DTD   XHTML   1.0   Transitional//EN "   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd ">
<html   xmlns= "http://www.w3.org/1999/xhtml ">
<head>
<meta   http-equiv= "Content-Type "   content= "text/html;   charset=gb2312 "   />
<title> 无标题文档 </title>
<script>
<!--
function   read()
{
var   request;
try   {
request   =   new   XMLHttpRequest();
}
catch(e){
request   =   new   ActiveXObject( "Microsoft.XMLHTTP ");
}
request.open( "get ", "gadget.xml ",false);
request.send()
var   bob=request.responseText;
alert( "返回的信息为: "+bob)
}
//-->
</script>
</head>
<body>
<input   id= "name "   name= "name "   type= "button "   Value= "测试 "   onclick= "return   read(); ">
</body>
</html>
//这是第一个文件


<?xml   version= "1.0 "   encoding= "utf-8 "   ?>
<gadget>
<name> mini   Player! </name>
<namespace> miniPlayer </namespace>
<version> 1.0 </version>
<author   name= "Mictel ">
<logo   src= "icon.png "/>
</author>
<copyright> 2007 </copyright>
<description> Vista   边栏工具   Windows   mini   Player! </description>
<icons>
        <icon   height= "128 "   width= "128 "   src= "icon.png "/>
  </icons>
<hosts>
<host   name= "sidebar ">
<base   type= "HTML "   apiVersion= "1.0.0 "   src= "VistaMP.html "   />
<permissions> full </permissions>
<platform   minPlatformVersion= "1.0 "   />
<defaultImage   src= "icon.png "/>
</host>
</hosts>
</gadget>
//这是第二个文件


以上文件测试成功.得到的是XML文件的全部信息.我的想法是:不是得到全部的信息.我只要XML里的某一条信息..如:(Vista   边栏工具   Windows   mini   Player!).想求几位高手帮帮我..在第一个文件的基础上帮我完成这个功能.小弟感激不尽..不够可以再散分的..

------解决方案--------------------
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN " "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd ">
<html xmlns= "http://www.w3.org/1999/xhtml ">
<head>
<meta http-equiv= "Content-Type " content= "text/html; charset=gb2312 " />
<title> 无标题文档 </title>
<script>
<!--
function read()
{
var request;
try {
request = new XMLHttpRequest();
}
catch(e){
request = new ActiveXObject( "Microsoft.XMLHTTP ");
}
request.open( "get ", "gadget.xml ",false);
request.send()
var bob=request.responseText;
alert( "返回的信息为: "+bob)

var doc = new ActiveXObject( "MSXML2.DOMDocument ")
doc.loadXML(bob);
var node = doc.selectSingleNode( "//description ");
alert(node.text);
node = null;
doc = null;
}
//-->