JQuery :: Hover Over Image Selected On Current Page?

I'm trying to get the hover over image selected based on the current page. I've used an external jquery.url.js library to access file and href information. The if statement is reached correctly, but I can't get the code within it to work. Each image is stored within an anchor and, as with the hover code (included), I'm trying to change the end of its source file name from '_off'to '_on' so it's active.

$(function () {
$("img.rollover").hover(
function () {
this.src = this.src.replace("_off", "_on");
},
function () {
this.src = this.src.replace("_on", "_off");
});
$page = jQuery.url.attr("file");
$('#menu tr td a').each(function () {
var $href = $(this).attr('href');
if ($href == $page) {
$("img", this).src.replace("_off", "_on");
}});