function maskcUserFB(str){

    if (window.XMLHttpRequest)
      {// code for IE7+, Firefox, Chrome, Opera, Safari
      xmlhttp=new XMLHttpRequest();
      }
    else
      {// code for IE6, IE5
      xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
    
    xmlhttp.open("GET","http://www.maskc.org/user_auth.php?q="+str,true);
    xmlhttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
    xmlhttp.send();

  }