Jquery: Unobtrusive JavaScript for Setting Up Rollovers

/**
 * Creates rollover functionality in JavaScript
 * requires JQuery
 * Rollovers should by default have their off state as the 
 * original image src. Set the on and off markers with the 
 * variables on the first two lines. By default they are 
 * _on and _off (i.e. rollover_off.jpg, rollover_on.jpg.)
 */
function createRollovers() {
    var onText = "_on",
        offText = "_off";
 
    $('img.rollover' ).each( function() {

        var onImg = $(this).attr('src').replace(offText,onText),
            offImg = $(this).attr('src').replace(onText,offText);
        
        $(this).bind('mouseenter', function () {
            $(this).attr('src', onImg );
        });
        $(this).bind('mouseleave', function () {
            $(this).attr('src', offImg );
        });
    });
 
    return;
}

$(document).ready(function () {
    createRollovers();
});