// Navigation Function
function sg_loadNav() {

	var navTable = document.getElementById('main-nav');
	var imgs = navTable.getElementsByTagName('img');
	var pload = '';

	for (var i=0;i<imgs.length;i++) {

		var el = imgs[i];
		if (el.src.indexOf('-over.gif') == -1) {
			el.onmouseover = function() { sg_navSwap(this, 'over'); }
			el.onmouseout = function() { sg_navSwap(this, 'out'); }
			
			// Add to preload flag
			osrc = el.getAttribute('src');
			osrc = osrc.replace('.gif','-over.gif');
			sg_addPreloadImg(osrc);	
		}
		
	}
}

function sg_navSwap(el,action) {
	if (action == 'over')
		el.src = el.src.replace('.gif','-over.gif');
	else
		el.src = el.src.replace('-over.gif','.gif');
}

// Preload Logic
var sg_preloadImgArgs= new Array();
var sg_preloadImgQueue = new Array();

function sg_preloadImages() {
	for (var i=0;i<sg_preloadImgQueue.length;i++){
		sg_preloadImgArgs[i]=new Image();
		sg_preloadImgArgs[i].src=sg_preloadImgQueue[i];
	}
}

function sg_addPreloadImg(args) {
	for (var i=0;i<sg_addPreloadImg.arguments.length;i++) {
		var src = sg_addPreloadImg.arguments[i];
		if (!sg_preloadImgQueue.in_array(src)) {
			//console.log(src);
			sg_preloadImgQueue.push(src);
		}
	}	
}

Array.prototype.in_array = function(obj){ 
	return new RegExp('(^|\,)'+obj+'(\,|$)','gi').test(this);
}