var height, width, wallpaperId;


function getParameter( name ) {
    var url = window.location.href;
    var paramsStart = url.indexOf("?");

    if(paramsStart == -1)
        return "";

    var paramString = url.substr(paramsStart + 1);
    var tokenStart = paramString.indexOf(name);
    if(tokenStart != -1){
     paramToEnd = paramString.substr(tokenStart + name.length + 1);
     var delimiterPos = paramToEnd.indexOf("&");

     if(delimiterPos == -1)
        return paramToEnd;
     else return paramToEnd.substr(0, delimiterPos);

    }
}
   
function maintainSize( minWidth, minHeight, div ) {
    if ( window.innerHeight ){
        height = parseInt(window.innerHeight);
        width = parseInt(window.innerWidth);			                
    }else {
        height = parseInt(document.body.offsetHeight);
        width = parseInt(document.body.offsetWidth);			                    
    }			
    height = ( height >  minHeight ) ? '100%' : minHeight + 'px';
    width = ( width >  minWidth ) ? '100%' : minWidth + 'px';
    var flash = document.getElementById( div );
    
    flash.style.height= height;
    flash.style.width = width;
}


function getWallpaperId() {    
    var wId;
    var wForceId = getParameter("w");
        
    if ( wForceId != null && wForceId.length > 0 )
        return wForceId;

    wId = value = readCookie("wId");    
    if ( wId == null ) {
        wId = Math.round( 3 * Math.random() );       
        if ( wId == 0 ) wId = 1;
        createCookie("wId",wId);
    }        
    return wId;
}


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);
}


/* Add wallpaper */

function addOnLoadEvent(func)
{	
	var oldonload = window.onload;
	if (typeof window.onload != 'function'){
    	window.onload = func;
	} else {
		window.onload = function(){
		oldonload();
		func();
		}
	}
}

function randomBg() {
    document.body.background = "images/mainbg" + getWallpaperId() +".jpg";
}

wallpaperId = getWallpaperId();
addOnLoadEvent( randomBg );