function preload() {    
		this.length = preload.arguments.length;
	    for (var i = 0; i < this.length; i++) {
			this[i+1] = new Image();
			this[i+1].src = preload.arguments[i];    
		}
	}
	if (document.images) {
	    var imgs = new preload(
	        "images/nav/searchrates-off.gif",
	        "images/nav/searchrates-on.gif"
			)
	}
	function swap(imgName) {
		if (document.images) {
			var test = document.images[imgName].src;
			if (test.indexOf("off")!=-1) {
				document.images[imgName].src = "/images/nav/"+imgName+"-on.gif";
			}
			else {
				document.images[imgName].src = "/images/nav/"+imgName+"-off.gif";
			}
		}
	}