jquery checkbox 多选/反选 插件

(function($) {
    $.fn.MultiCheck = function(options) {

        settings = $.extend({
            groupName: '',
            checked: true
        }, options || {});

        var groupTarget = (settings.groupName == '') ? ':checkbox' : 'input[name=' + settings.groupName + ']';

        switch (settings.checked) {
            case true:
                $(groupTarget).each(function() { this.checked = true; });
                break;
            default:
                $(groupTarget).each(function() { this.checked = false; });
                break;
        }
    };