// JScript File

//Modified by Swapnil for retaining background picture even if new page is loaded
//(Please read below information before making any changes in the javascript)

//For this I have used Cookies to save or retain current state (image url, seconds overed, image count)
//Expiry of cookie is not set because when browser is closed all the cookies in the program used should get deleted.
//Hence when user once again go to the website by closing the browser previously he/she should get 
//1st background image loaded every time he/she visits the website.

//Cookie variables Used:-
//currentbackImage=stores current background image url.
//currentbackImageDesc=stores current background image's description which is displayed below right corner parallel to next image.
//Currenttimeinsec=stores time in seconds pass of 30
//ImageCount=stores count of image.

    var secs = 30;
    var secsforchangedimagefromnext=30;
    // The values for secs & secsforchangedimagefromnext should be same.
    var timerID = null;
    var delay = 1000;
    var imagesauto=["Niagara_Falls_bg.jpg", "Petronas_Twin_Towers_bg.jpg", "egypt_bg.jpg", "Taj_Mahal_bg.jpg", "eiffel_tower_bg.jpg"];  
    var oldmagauto = 0;
    var img = "images/";
    var iText = new Array()
    iText[0] = "America holidays";
    iText[1] = "Far East holidays"
    iText[2] = "Egypt holidays"
    iText[3] = "India holidays";
    iText[4] = "Paris holidays"
    
    var imgColour=["img1","img2","img3","img4","img5"];
    var imgMax = imgColour.length;
     
    function chgBkgd()
    {
    var div = "backimage"
	if (!document.getElementById(div)) return false;
	var $head = document.getElementById(div);
	var $bkgd = $head.style.backgroundImage;
	
	    if (readCookie("ImageCount")!=null)
        {
            oldmagauto=readCookie("ImageCount");
         }
        
	var ImgAdd = "url(" + img + imagesauto[oldmagauto] + ")";
	createCookie("currentbackImage",ImgAdd);
	var thisID;
	
	if ($bkgd != ImgAdd) 
	{
		$head.style.backgroundImage = ImgAdd;
	}

	document.getElementById('imgDesc').innerHTML=iText[oldmagauto];
	createCookie("currentbackImageDesc",iText[oldmagauto]);
	createCookie("Currenttimeinsec",secsforchangedimagefromnext);
	secs=secsforchangedimagefromnext;
		
	if (oldmagauto==imagesauto.length - 1)
	{
	    oldmagauto = 0;
	}
	else
	{
	    oldmagauto = Number(oldmagauto) + 1;
	}
	createCookie("ImageCount",oldmagauto);
	
    }

function InitializeTimer()
{

    if ((readCookie("currentbackImage")!=null) && (readCookie("currentbackImageDesc")!=null))
    {
        document.getElementById("backimage").style.backgroundImage=readCookie("currentbackImage");
        document.getElementById('imgDesc').innerHTML=readCookie("currentbackImageDesc");
     }
     else
     {
        document.getElementById("backimage").style.backgroundImage="url(" + img +"eiffel_tower_bg.jpg)";
        document.getElementById('imgDesc').innerHTML="Paris holidays";
     }
     
    if (readCookie("Currenttimeinsec")!=null)
    {
        secs=readCookie("Currenttimeinsec");
    }
    StartTheTimer();
}

function StartTheTimer()
{
    if (secs==0)
    {
     if (readCookie("ImageCount")==null)
        {
            chgBkgdauto(Number(oldmagauto)+1);
        }
        else
        {
            oldmagauto=readCookie("ImageCount");
            chgBkgdauto(Number(oldmagauto)+1);
        }
        secs = 30;
        createCookie("Currenttimeinsec",secs);
        timerID = self.setTimeout("StartTheTimer()", delay);        
    }
    else
    {
        secs = secs - 1;
        createCookie("Currenttimeinsec",secs);
        if (readCookie("currentbackImage")!=null)
        {
            document.getElementById("backimage").style.backgroundImage=readCookie("currentbackImage");
        }
        
        if(readCookie("currentbackImageDesc")!=null)
        {
            document.getElementById('imgDesc').innerHTML=readCookie("currentbackImageDesc");
        }
        timerID = self.setTimeout("StartTheTimer()", delay);
    }
}

function chgBkgdauto(imag)
{
	var div = "backimage";
	if (!document.getElementById(div)) return false;
	var $head = document.getElementById(div);
	var $bkgd = $head.style.backgroundImage;
	var ImgAdd = "url(" + img + imagesauto[oldmagauto] + ")";
	document.getElementById('imgDesc').innerHTML=iText[oldmagauto];
	createCookie("currentbackImageDesc",iText[oldmagauto]);
	if (imag==imagesauto.length)
	{
	    oldmagauto = 0;
	    eraseCookie("ImageCount");
	}
	else
	{
	    oldmagauto = imag;
	    createCookie("ImageCount",oldmagauto);
	}
    $head.style.backgroundImage = ImgAdd;
    createCookie("currentbackImage",ImgAdd);
 }



    function createCookie(name,value,days) {
        if (days) {
        var date = new Date();
        date.setTime(date.getTime()+(days*24*60*60*1000));
        var expires = "; expires="+date.toGMTString();
        }
        else var expires = "";
        document.cookie = name+"="+value+expires+"; path=/";
        }

    function readCookie(name) {
        var nameEQ = name + "=";
        var ca = document.cookie.split(';');
        for(var i=0;i < ca.length;i++) {
        var c = ca[i];
        while (c.charAt(0)==' ') c = c.substring(1,c.length);
        if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
        }
        return null;
        }

    function eraseCookie(name) {
        createCookie(name,"",-1);
        }