Ajax fungerar endast i FF

<script language="Javascript">
function xmlhttpPost(strURL) {
  var xmlHttpReq = false;
  var self = this;
  // Mozilla/Safari
  if (window.XMLHttpRequest) {
    self.xmlHttpReq = new XMLHttpRequest();
  }
  // IE
  else if (window.ActiveXObject) {
    self.xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
  }
  self.xmlHttpReq.open('POST', strURL, true);
  self.xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
  self.xmlHttpReq.onreadystatechange = function() {
	
  
  if (self.xmlHttpReq.readyState == 1) {
      updatepage('<br /><br /><img src="loader.gif" border="0" alt="" style="margin-left:15px;" />');
    }

 
    if (self.xmlHttpReq.readyState == 4) {
      updatepage(self.xmlHttpReq.responseText);
    }
  }
  self.xmlHttpReq.send(getquerystring());
}

function getquerystring() {
  var form   = document.forms['feeds'];
  var word = form.feed.value;
  qstr = 'feed=' + escape(word);
  return qstr;
}

function updatepage(str){
  document.getElementById("result").innerHTML = str;
}
</script>

xmlHttpReq = new XMLHttpRequest();