AJAX赚容火狐

var xmlHttp;
if (window.ActiveXObject) { 
      xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
else if (window.XMLHttpRequest) { 
      xmlHttp = new XMLHttpRequest();
}
xmlHttp.open("POST", "?type=f&pid="+productid, false);
xmlHttp.send("");

用这个就OK了