var selectPage = 0;


function loadPage(page){
	var htmlRequestLoadPage = ajaxFunction();
	if (htmlRequestLoadPage==null){ // If it cannot create a new Xmlhttp object.
		alert ("Browser does not support HTTP Request");
		return;
	} 

	htmlRequestLoadPage.onreadystatechange = function(){
		if(htmlRequestLoadPage.readyState == 4){
								clearTimeout(htmlRequestLoadPageTimer);
                        if (htmlRequestLoadPage.status == 200){
 									var reply = htmlRequestLoadPage.responseText;
 									document.getElementById("plainBody").innerHTML = reply;
 									adjustArrow();
									var i;
									for(i=0; i<7; i++){
 										postCache[i] = document.getElementById("post" + postId[i]).innerHTML;
 									}
 									if(firstTime == 0)
 										checkSingle();
 									firstTime = 1;
 									window.scroll(0, 580);
								}
                        else {
                        	htmlRequestLoadPage.abort();
                           loadPage(page);
                        }
		}
	}
	var htmlRequestLoadPageTimer = setTimeout(function() {
       htmlRequestLoadPage.abort();
       loadPage(page);
     }, 15000);
   
   if(page == "forward")
   	selectPage ++;
   else if(page == "backward")
   	selectPage --;
   else
   	selectPage = page;
	htmlRequestLoadPage.open("GET", "plain.php?page="+ selectPage +"&random=" + randomNumber(), true);
	htmlRequestLoadPage.send(null);
}

var forwardArrowCache;
var backwardArrowCache;

function adjustArrow(){
	if(selectPage == 0){
		backwardArrowCache = document.getElementById("backwardArrowCache").innerHTML;
		document.getElementById("backwardArrowCache").innerHTML = "";
	}
	else {
		document.getElementById("backwardArrowCache").innerHTML = backwardArrowCache ;
		document.getElementById("backwardArrow").style.background = 'url(img-template/backward-arrow.png)';
	}
	document.getElementById("gogoPage").value = selectPage;
}

function IsNumeric(strString) {
   var strValidChars = "0123456789.-";
   var strChar;
   var blnResult = true;

   if (strString.length == 0) return false;

   for (i = 0; i < strString.length && blnResult == true; i++){
      strChar = strString.charAt(i);
      if (strValidChars.indexOf(strChar) == -1) {
         blnResult = false;
      }
   }
   return blnResult;
}

function goToPage(){
	if(IsNumeric(document.goTo.page.value))
		fetchPostArray(document.goTo.page.value);
	return false;
}