var loadingImg = new Image();
loadingImg.src = location.protocol + "//" + location.hostname + "/Images/loading.gif";

function AjaxCall(url, objectId, IsCenter)
{
  document.getElementById(objectId).innerHTML = "<table border=\"0\" cellpadding=\"10\" cellspacing=\"0\" style=\"background-color: #BBC6DC; filter: alpha(opacity=70);\"><tr><td valign=\"middle\" style=\"font-family: Arial; color: #ffffff; font-size: 12px; font-weight: bold;\"><center><img src=\"" + loadingImg.src + "\" style=\"vertical-align: middle;\" /><br />Cargando...</center></td></tr></table>";

  //return;
  var objXMLHttp = getXMLHttp();
  if(objXMLHttp == null)
  {
    document.getElementById(objectId).innerHTML = "Error de Ajax";
    return;
  }
  objXMLHttp.onreadystatechange = function()
  {
    showResponseText(objXMLHttp, objectId, IsCenter)
  }
  url += "&" + Math.random(); 
  objXMLHttp.open("GET", url, true) // asignamos los mtodos open y send
  objXMLHttp.send(null)
}

function AjaxExec(url)
{
  var objXMLHttp = getXMLHttp();
  if(objXMLHttp != null)
  {
    objXMLHttp.open("POST", url, true) // asignamos los mtodos open y send
    objXMLHttp.send(null)  
  }
}

function getXMLHttp() 
{
  var xmlhttp = null;
	try 
	{
		xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
  } 
  catch (e) 
  {
    try 
    {
      xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    } 
    catch (E) 
    {
      xmlhttp = false;
    }
  }
  if (!xmlhttp && typeof(XMLHttpRequest) != "undefined") 
    xmlhttp = new XMLHttpRequest();
  return xmlhttp
}

function showResponseText(objXMLHttp, objectId, IsCenter)
{
  if (objXMLHttp.readyState == 4 && (objXMLHttp.status==200 || window.location.href.indexOf("http")==-1))
  {
    document.getElementById(objectId).innerHTML = objXMLHttp.responseText;
  }
    if(IsCenter)
    {
      document.getElementById(objectId).style.top = document.body.scrollTop + ((document.body.clientHeight / 2) - (document.getElementById(objectId).offsetHeight / 2));
      document.getElementById(objectId).style.left = document.body.scrollLeft + ((document.body.clientWidth / 2) - (document.getElementById(objectId).offsetWidth / 2));    
      if(navigator.appName == "Netscape")
      {
        document.getElementById(objectId).style.top += "px";
        document.getElementById(objectId).style.left += "px";
      }    
    }
}