效果实现共需三个文件：

1、test.html    内容：

2、radioChecked.js     内容

    ;(function($, window, document, undefined){    var MyPlugin = function(obj){        this.$object = obj,        this.className = this.getClass(),        this.elementName = this.getElementName()        //this.options = $.extend({}, this.defaults, opt)    }    MyPlugin.prototype = {        init: function() {            if(this.$object.data('check') == '1'){                $(':radio[name="'+ this.elementName +'"]').each(function(){                    $(this).data('check','1');                });                this.$object.data('check','2');                alert('选中');            }            else if(this.$object.data('check') == '2'){                this.$object.data('check','1');                this.$object.removeAttr('checked');                alert('取消选中');            }        },        getClass: function(){            return this.$object.attr('class');        },        getElementName: function(){            return this.$object.attr('name');        },        setDataAttr: function(){            $('.'+this.className).data('check','1');        }    }        $.fn.radioChecked = function(){        return new MyPlugin(this);    }})(jQuery, window, document);

3、jquery1.8.2.js