相容IE和firefox 操作XML的 javascript

<script type="text/javascript">
var xmlDoc
function loadXML()
{
//load xml file
// code for IE
if (window.ActiveXObject)
  {
  xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
  xmlDoc.async=false;
  xmlDoc.load("note.xml");
  getmessage()
  }
// code for Mozilla, etc.
else if (document.implementation &&
document.implementation.createDocument)
  {
  xmlDoc= document.implementation.createDocument("","",null);
  xmlDoc.load("note.xml");
  xmlDoc.onload=getmessage
  }
else
  {
  alert('Your browser cannot handle this script');
  }
}

function getmessage()
{
document.getElementById("to").innerHTML=
xmlDoc.getElementsByTagName("to")[0].firstChild.nodeValue
document.getElementById("from").innerHTML=
xmlDoc.getElementsByTagName("from")[0].firstChild.nodeValue
document.getElementById("message").innerHTML=
xmlDoc.getElementsByTagName("body")[0].firstChild.nodeValue
}
</script>