function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}
function createRequestObject() {
  var ro;
  var browser = navigator.appName;
  if(browser == "Microsoft Internet Explorer"){
    ro = new ActiveXObject("Microsoft.XMLHTTP");
  }else{
    ro = new XMLHttpRequest();
  }
  return ro;
}
var http = createRequestObject();