sort cardpool gift cards by discount amount

cardpool.js

(function() {
    // http://www.cardpool.com/buy-gift-cards
    var table = $($("table.merchants_grid")[0]);

    var boxes = table.find("td.merchant_cell");
    boxes.sort(function(a, b) {
        var val1 = parseInt($(a).find('.merchant_discount').text()),
            val2 = parseInt($(b).find('.merchant_discount').text());    
        return val2 - val1;
    });

    for (var i = 0; i < boxes.length; i++) {
        var tr = $(table.find("tr")[Math.floor(i / 5)]);
        tr.append(boxes[i]);
    }
    
    // make out-of-stock obvious
    $($("table.merchants_grid")[1]).css("opacity", 0.25);
})();