// JavaScript Document
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);
}

function setbg(zmena){
var cislo = readCookie('cislo');
if (zmena==1) cislo++;
else cislo--;
if (cislo>19) cislo=0;
else if (cislo<0) cislo=19;
createCookie('cislo',cislo,1);
document.getElementById('bodycko').style.backgroundImage='url(_images/wall-'+cislo+'.png)';
}

function init(){
var cislo = readCookie("cislo");
if (!cislo) cislo=0;
document.getElementById('bodycko').style.backgroundImage='url(_images/wall-'+cislo+'.png)';
createCookie('cislo',cislo,1);
}