//重写ajax，post增加loading
(function ($) {
    var _ajax = $.ajax;

    $.ajaxWithLoading = function (opt) {
        var fn = {
            error: function (XMLHttpRequest, textStatus, errorThrown) { },
            success: function (data, textStatus) { }
        };

        if (opt.error) {
            fn.error = opt.error;
        }
        if (opt.success) {
            fn.success = opt.success;
        }

        var $loading = $('#loading');
        var _opt = $.extend(opt, {
            error: function (XMLHttpRequest, textStatus, errorThrown) {

                $loading.hide();
                fn.error(XMLHttpRequest, textStatus, errorThrown);
            },
            success: function (data, textStatus) {

                $loading.hide();
                fn.success(data, textStatus);
            }
        });

        $loading.show();
        $.ajax(_opt);
    };

    $.getWithLoading = function (url, data, callback, type) {
        return $.ajaxWithLoading({
            url: url,
            type: 'get',
            dataType: type,
            data: data,
            success: callback
        });
    };

    $.postWithLoading = function (url, data, callback, type) {
        return $.ajaxWithLoading({
            url: url,
            type: 'post',
            dataType: type,
            data: data,
            success: callback
        });
    };
})($);

$.fn.extend({
    submitWithLoading: function () { 
        var $loading = $('#loading');
        
        $loading.show();
        $(this).submit();
    }
});