function Ajax(obj) {
   var ajaxObj;
	
   try {
      // Firefox, Opera 8.0+, Safari...
      ajaxObj=new XMLHttpRequest();
   } catch (e) {
      // Internet Explorer
      try {
         ajaxObj=new ActiveXObject("Msxml2.XMLHTTP");
      } catch (e) {
         try {
            ajaxObj=new ActiveXObject("Microsoft.XMLHTTP");
         } catch (e) {
            alert("Seu navegador não possui suporte ao AJAX!");
            return false;
         }
      }
   }
   ajaxObj.onreadystatechange=function() {
      if(ajaxObj.readyState==4) {
        obj.response(ajaxObj.responseText);
      }
   }
   ajaxObj.open(obj.method,obj.url,true);
   ajaxObj.send(obj.params);
 
}