var xmlHttp;
  function doRequest() {
    xmlHttp = GetXmlHttpObject();
    if (xmlHttp == null) {
      alert ("Browser does not support HTTP Request");
      return;
    }
    var url = "/php/reloadImage.php";
    xmlHttp.onreadystatechange = stateChanged;
    xmlHttp.open("GET",url,true);
    xmlHttp.send(null);
  }//end doRequest()
  
  function stateChanged() {
    if (xmlHttp.readyState == 4 || xmlHttp.readyState == "complete") {
      document.getElementById("captcha").innerHTML = xmlHttp.responseText;
    }
  }//end stateChanged()
  
  function GetXmlHttpObject() {
    var objXMLHttp = null;
    if (window.XMLHttpRequest) {
      objXMLHttp = new XMLHttpRequest();
    }
    else if (window.ActiveXObject) {
      objXMLHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    return objXMLHttp;
  }//end GetXmlHttpObject()

function makeDoubleDelegate(function1, function2) {
  return function() {
    if (function1)
      function1();
    if (function2)
      function2();
  }
}

window.onload = makeDoubleDelegate(window.onload, doRequest );