function Cargar(url, target){
   var req;
   if (window.XMLHttpRequest) {
      req = new XMLHttpRequest();
   }
   else
 
      if (window.ActiveXObject) {
         req = new ActiveXObject("Microsoft.XMLHTTP");
      }
      document.getElementById(target).innerHTML = '<img src="loading1.gif" align="middle" />';
      req.onreadystatechange = function()
      {
         if (req.readyState == 4)
         {
            if (req.status == 200)
            {
               document.getElementById(target).innerHTML = req.responseText;
            }
            else
            {
               document.getElementById(target).innerHTML = "Error";
            }
         }
      }
      req.open("GET", url, true);
      req.send("");
}