$(document).ready(function() {

        // Preload all rollovers
        $("#nav img").each(function() {
            // Set the original src
            rollsrc = $(this).attr("src");
            rollON = rollsrc.replace(/.gif$/ig,"_over.gif");
            $("<img>").attr("src", rollON);
        });

        // Navigation rollovers
        $("#nav a").mouseover(function(){
            imgsrc = $(this).children("img").attr("src");
            matches = imgsrc.match(/_over/);

            // don't do the rollover if state is already ON
            if (!matches) {
            imgsrcON = imgsrc.replace(/.gif$/ig,"_over.gif"); // strip off extension
            $(this).children("img").attr("src", imgsrcON);
            }

        });
        $("#nav a").mouseout(function(){
            $(this).children("img").attr("src", imgsrc);
        });


    });