var frameDelay = 10;
var rate = 5;
var maxHover = 16;
var maxUnHover = -2;
var navlink = new Array();

function init(){
	navlink = document.getElementById('nav').getElementsByTagName('a');
	for(i=0;i<navlink.length;i++){
		navlink[i].bgVPos = -36;
		navlink[i].bgTPos = -36;
		navlink[i].onmouseover = hover;
		navlink[i].onmouseout = unHover;
	}
	setTimeout("animStep()",frameDelay);
}

function hover(){
	this.bgTPos = -2;
}

function unHover(){
	this.bgTPos = -36;
}

function animStep(){
	for(i=0;i<navlink.length;i++){
		dist = navlink[i].bgTPos - navlink[i].bgVPos;
		dist = dist / rate;
		dist = max(min(dist,maxHover),maxUnHover)
			
		navlink[i].bgVPos += dist;
		navlink[i].style.backgroundPosition = "50% " + Math.round(navlink[i].bgVPos) + "px";
	}
	setTimeout("animStep()",frameDelay);
}

function min(val1,val2){
	switch(val1 < val2){
		case true:
			return val1;
			break;
		case false:
			return val2;
			break;
	}
}

function max(val1,val2){
	switch(val1 > val2){
		case true:
			return val1;
			break;
		case false:
			return val2;
			break;
	}
}

window.onload = init;