// JavaScript Document

function getXMLHttp()
{
  var xmlHttp

  try
  {
    //Firefox, Opera 8.0+, Safari
    xmlHttp = new XMLHttpRequest();
  }
  catch(e)
  {
    //Internet Explorer
    try
    {
      xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
    }
    catch(e)
    {
      try
      {
        xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
      }
      catch(e)
      {
        alert("Your browser does not support AJAX!")
        return false;
      }
    }
  }
  return xmlHttp;
}



function MakeRequest(element, url, clearoverlay)
{
	if (clearoverlay){
		overlayclear();
	}
  var xmlHttp = getXMLHttp();
  
  xmlHttp.onreadystatechange = function()
  {
    if(xmlHttp.readyState == 4)
    {
      HandleResponse(xmlHttp.responseText, element);
    }
  }

  xmlHttp.open("GET", url, true); 
  xmlHttp.send(null);
}


function HandleResponse(response, element)
{
  document.getElementById(element).innerHTML = response;
}


function overlay(url) {
	MakeRequest("overlay", url);
	el = document.getElementById("overlay");
	el.style.visibility = "visible";//(el.style.visibility == "visible") ? "hidden" : "visible";
}

function overlayclose(){
	el = document.getElementById("overlay");
	el.style.visibility = "hidden";
	el.innerHTML = "<div style='width:100%; height:20px; position:absolute; top:50%; text-align:center;'><img src='images/ajax-wait.gif' width='16' height='16' /></div>";
}

function overlayclear(){
	el = document.getElementById("overlay");
	el.innerHTML = "<div style='width:100%; height:20px; position:absolute; top:50%; text-align:center;'><img src='images/ajax-wait.gif' width='16' height='16' /></div>";
}