$(document).ready(function () {
    $(".mainNav a").mouseover(function () {
        $(".mainNav a").attr("class", "");
        $("#" + this.id).attr("class", "actived");
        var currentMenuNo = parseInt(this.id.substring(1));
        $(".secondNav div").each(function () {
            $(this).hide();
            $("#subNav" + currentMenuNo).show();
        });
    });
});