function linkBg() {
			var anchors = document.getElementById("tab-nav1").getElementsByTagName("a");
			for (var i=0; i<anchors.length; i++) {
	        	var anchor = anchors[i];
				anchor.onmouseover=function() {
					this.parentNode.className+=(this.className.length>0? " ": "") + "hf";
				}
				anchor.onfocus=function() {
					this.parentNode.className+=(this.className.length>0? " ": "") + "hf";
				}
				anchor.onmouseout=function() {
					this.parentNode.className=this.className.replace(new RegExp("( ?|^)hf\\b"), "");
				}
				anchor.onblur=function() {
					this.parentNode.className=this.className.replace(new RegExp("( ?|^)hf\\b"), "");
				}
			}
		}
		window.onload=linkBg;