function loadNav () {
var ipath = new Array();

	var anchors = document.getElementById("nav").getElementsByTagName("a");
	img_r = new Array();
	for(var i = 0; i < anchors.length; i++) {
		var isrc = anchors[i].getElementsByTagName("img")[0].src;
		var iext = isrc.substring(isrc.lastIndexOf('.'));
		ipath[i] = isrc.substring(0,isrc.lastIndexOf('.'));
		img_r[i] = new Image();
		img_r[i].src = ipath[i] + "_r";
		anchors[i].id = i;
		if(ipath[i].lastIndexOf('_static') < 0){
			anchors[i].getElementsByTagName("img")[0].onmouseover = function () {
				this.src = img_r[this.parentNode.id].src + iext; 
			}
			anchors[i].getElementsByTagName("img")[0].onmouseout = function () {
				this.src = ipath[this.parentNode.id] + iext;
			}
		}
	}
}

addLoadEvent(loadNav);