//NOTE: If there are problems with the script hanging, may want
//      to use XMLHttpRequest asynchronously (the last parameter
//      of pageRequest.open would be true)
//      This would require using the onreadystatechange event
//      e.g. pageRequest.onreadystatechange  = DisplayAd
//      where DisplayAd would now handle changing the innerHTML of the div

function HttpRequest(url){

var pageRequest = false //variable to hold ajax object
/*@cc_on
   @if (@_jscript_version >= 5)
      try {
      pageRequest = new ActiveXObject("Msxml2.XMLHTTP")
      }
      catch (e){
         try {
         pageRequest = new ActiveXObject("Microsoft.XMLHTTP")
         }
         catch (e2){
         pageRequest = false
         }
      }
   @end
@*/

if (!pageRequest && typeof XMLHttpRequest != 'undefined')
   pageRequest = new XMLHttpRequest()

if (pageRequest){ //if pageRequest is not false
   pageRequest.open('GET', url, false) //get page synchronously 
   pageRequest.send(null)
   if (window.location.href.indexOf("http")==-1 || pageRequest.status==200)
     return pageRequest.responseText
   }
   return 'Failed to retrieve dynamic content';
}

var intervalID;
var adId = 0;
var adCount = 0;
var divID;
var zone="today";

function startRotator(adDivID,adZone)
{
  divID = adDivID;
  zone = adZone;
  
  RefreshAd(1); //start up ad rotator with a random ad
  
  //cgi page contains two hidden divs so the script knows
  //1) the number of ads in the database
  //2) the starting ad (that was chosen randomly by the cgi script)
  elem = document.getElementById("adCountDiv");
  adCount = parseInt(unescape(elem.innerHTML));
  elem = document.getElementById("curAdDiv");
  adId = parseInt(unescape(elem.innerHTML))+1;
  
  //use setInterval to refresh the ad every 7 seconds
  intervalID = setInterval('RefreshAd(0)',7000);
}


function prevAd()
{
  clearInterval(intervalID);
  
  //since RefreshAd increments adId after displaying,
  //the id of the currently displayed ad is one less than adId
  //so we need to decrement adId by two in order to go to the last displayed ad
  adId = adId-2;
  
  RefreshAd(0); //do refresh now
  intervalID = setInterval('RefreshAd(0)',7000);
}
function nextAd()
{
  clearInterval(intervalID);
  
  //no increment needed (already done at the end of RefreshAd)
  RefreshAd(0);
  
  intervalID = setInterval('RefreshAd(0)',7000);
}
function RefreshAd(randAd)
{
  elem = document.getElementById(divID);
  
  //make sure we have the right domain
  //HttpRequest won't work for a different domain, and it
  //thinks http://www.site.com is different than http://site.com 
  var mydomain="http://"+window.location.hostname;
  
  if (adId>=adCount)
    adId = 0; //start at the first ad
  else if (adId<0)
    adId = adCount-1; //go to the last ad
    
  if (randAd==0) //get the next ad in sequence
  { 
    elem.innerHTML = HttpRequest(mydomain+"/longviewkelso/cgi-bin/ads/ads-new.cgi?zone="+zone+"&width=170&height=180&ad="+adId+"&action=showsads");
  }
  else //generate a random ad
  {
    elem.innerHTML = HttpRequest(mydomain+"/longviewkelso/cgi-bin/ads/ads-new.cgi?zone="+zone+"&width=170&height=180&action=showsads");
  }
  adId = adId+1;
 
}