var keyHistory = new Array(11);
var keyCode = new Array(38,38,40,40,37,39,37,39,66,65,13);

function addKey(key){
	for(var i = 0; i < 10; i++)
		keyHistory[i] = keyHistory[i+1];
	keyHistory[10] = key;
}

function checkKeys(){
	for(var i = 0; i < 11; i++)
		if(keyHistory[i]!=keyCode[i])
			return false;
	return true;
}

function keyup(e) {
	if(!e)
		e = event;
	addKey(e.which);
	if(checkKeys())
		$("#header a").css({'background-image' : 'url(/images/buttons/unicorn.jpg)'});
}

function initCode(){
	if (document.addEventListener)
	   document.addEventListener("keyup",keyup,false);
	else if (document.attachEvent)
	   document.attachEvent("onkeyup", keyup);
	else
	   document.onkeyup= keyup;
}