function md5(string) {
    var xmlHttp;
    try {
      xmlHttp=new XMLHttpRequest();
    }
    catch (e) {
      try {
        xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
      }
      catch (e) {
        try {
          xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
        }
        catch (e) {
          return false;
        }
      }
    }
    xmlHttp.onreadystatechange=function() {
      if (xmlHttp.readyState == 4) {
        return xmlHttp.responseText;      
      }
    }
    var url = "/query.php";
    url = url+"?mode=md5";
    url = url+"&s="+string;
    xmlHttp.open("GET",url,true);
    xmlHttp.send(null);  
  }