var host = 'http://'+location.host;
var req = null; 
var timeout = null;
var delay = 5000;
var previd;   
var nextid;

var READY_STATE_UNINITIALIZED = 0;
var READY_STATE_LOADING = 1;
var READY_STATE_LOADED = 2;
var READY_STATE_INTERACTIVE = 3;
var READY_STATE_INTERACTIVE = 3;
var READY_STATE_COMPLETE = 4;

//---------------------------------------------------------------------------------------// 

function sendRequest(url, params, HttpMethod){
  if(!HttpMethod) HttpMethod = "GET";

  req = initXMLHTTPRequest(); 
  req.onreadystatechange = onCheckState;
  req.open(HttpMethod,url,true);
  req.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
  req.send(params);
}
 
//---------------------------------------------------------------------------------------// 

function initXMLHTTPRequest(){
  var xRequest = null;
  
  if(window.XMLHttpRequest){
    xRequest = new XMLHttpRequest();
  }
  else if(typeof ActiveXObject != "undefined"){
    xRequest = new ActiveXObject("Microsoft.XMLHTTP");
  }
  return xRequest;
}

//---------------------------------------------------------------------------------------// 

function onCheckState(){
   
  var ready = req.readyState;
  var data = null;

  if(ready == READY_STATE_COMPLETE){
    data = req.responseText; 
    updatePage(data);
  }
}

//---------------------------------------------------------------------------------------// 

function updatePage(data){
  
  parts = data.split('<--->'); 
  
  document.images['galimg'].src = parts[0]; 
  
  cname = document.getElementById('galname');  
  cname.innerHTML = parts[1]; 
 
  cdesc = document.getElementById('galdesc');  
  cdesc.innerHTML = parts[2];
  
  previd = parts[3];
  nextid = parts[4];   
  
  cgalprev = document.getElementById('galprev'); 
  cgalnext = document.getElementById('galnext'); 
  
  if(previd>0) cgalprev.style.display = 'block';
  else cgalprev.style.display = 'none';
 
  if(nextid>0) cgalnext.style.display = 'block';
  else cgalnext.style.display = 'none';  
}

//---------------------------------------------------------------------------------------// 

function checkStatus(id, mode){
  gid = (mode) ? nextid : previd;
  url = host+'/gallery/get/'+gid+'.html';
  sendRequest(url);
}