$().ready(function () {
    $('.btn').mouseover(function () {
        var oldsrc = $(this).attr('src');
        var newsrc = $("." + $(this).attr('class').replace(' ', '.') + '.hidden').attr('src');
        $(this).attr('src', newsrc);
        $("." + $(this).attr('class').replace(' ', '.') + '.hidden').attr('src', oldsrc);
    }).mouseout(function () {
        var oldsrc = $(this).attr('src');
        var newsrc = $("." + $(this).attr('class').replace(' ', '.') + '.hidden').attr('src');
        $(this).attr('src', newsrc);
        $("." + $(this).attr('class').replace(' ', '.') + '.hidden').attr('src', oldsrc);
     });
});







//function MM_preloadImages() { //v3.0
//    var d = document; if (d.images) {
//        if (!d.MM_p) d.MM_p = new Array();
//        var i, j = d.MM_p.length, a = MM_preloadImages.arguments; for (i = 0; i < a.length; i++)
//            if (a[i].indexOf("#") != 0) { d.MM_p[j] = new Image; d.MM_p[j++].src = a[i]; }
//    }
//}


//function MM_swapImgRestore() { //v3.0
//    var i, x, a = document.MM_sr; for (i = 0; a && i < a.length && (x = a[i]) && x.oSrc; i++) x.src = x.oSrc;
//}


//function MM_findObj(n, d) { //v4.01
//    var p, i, x; if (!d) d = document; if ((p = n.indexOf("?")) > 0 && parent.frames.length) {
//        d = parent.frames[n.substring(p + 1)].document; n = n.substring(0, p);
//    }
//    if (!(x = d[n]) && d.all) x = d.all[n]; for (i = 0; !x && i < d.forms.length; i++) x = d.forms[i][n];
//    for (i = 0; !x && d.layers && i < d.layers.length; i++) x = MM_findObj(n, d.layers[i].document);
//    if (!x && d.getElementById) x = d.getElementById(n); return x;
//}


//function MM_swapImage() { //v3.0
//    var i, j = 0, x, a = MM_swapImage.arguments; document.MM_sr = new Array; for (i = 0; i < (a.length - 2); i += 3)
//        if ((x = MM_findObj(a[i])) != null) { document.MM_sr[j++] = x; if (!x.oSrc) x.oSrc = x.src; x.src = a[i + 2]; }
//}