编写自己的jQuery提示框（Tip）插件

//添加check和uncheck插件
jQuery.fn.extend({
  check: function() {
    return this.each(function() { this.checked = true; });
  },
  uncheck: function() {
    return this.each(function() { this.checked = false; });
  }
});
//插件的使用
$("input[type=checkbox]").check();
$("input[type=radio]").uncheck();

$(function(){
    var t = $(".weixin").Tip({
        title:'微信扫一扫',
        content:'<img src="img/weixin.jpg" width="160px" height="160px;">',
        html:true,
        direction:'bottom'
        });
    t.bind({
        mouseover:function(){
            t.Tip("show");   
        },
         mouseout:function() {
            t.Tip("hide");
        }
    });
});

defaultOptions :{
            title : '',//标题
            content : '',//内容
            direction : 'bottom',//弹出反向，相对于选中元素
            html : false,//是否允许内容为html元素
            template : '<div class="tip"><div class="tip-inner"><h3></h3><div class="tip-container"></div></div></div>'//弹出框模版
        }

!function($){
    var Tip = function(element, options){
        this.init(element, options);
    }
    Tip.prototype = {
        constructor : Tip,
        init : function(element, options){
            this.element = $(element);
            this.options = $.extend({},this.defaultOptions,options);
        },
        show : function() {
            if (!this.tip) {
                this.tip = this.getTip();
                var title = this.tip.find("h3"),
                    container = this.tip.find(".tip-container");
                //设置标题
                title.text(this.options.title);
                //设置内容
                if (this.options.html) {
                    container.html(this.options.content);
                } else {
                    container.text(this.options.content);
                }
                //添加tip到body
                $("body").append(this.tip);
                //计算tip的位置
                var eLeft = this.element.offset().left,
                    eTop = this.element.offset().top,
                    eWidth = this.element.innerWidth(),
                    eHeight = this.element.innerHeight(),
                    tipw = this.tip[0].offsetWidth,
                    tiph = this.tip[0].offsetHeight,
                    top,
                    left;
                switch(this.options.direction) {
                case 'top' :
                    top = eTop - tiph;
                    left = (eLeft - tipw/2) + eWidth/2;
                    this.tip.css({top: top, left: left});
                    break;
                case 'left' :
                    top = (eTop - tiph/2) + eHeight/2;
                    left = eLeft - tipw;
                    this.tip.css({top: top, left: left});
                    break;
                case 'bottom' :
                    top = eTop + eHeight;
                    left = (eLeft - tipw/2) + eWidth/2;
                    this.tip.css({top: top, left: left});
                    break;
                case 'right' :
                    top = (eTop - tiph/2) + eHeight/2;
                    left = eLeft + eWidth;
                    this.tip.css({top: top, left: left});
                    break;
                default:
                    break;
                }
            } else {
                this.tip.css({display:'block'});
            }
        },
        hide : function() {
            this.getTip().css({display:"none"});
        },
        getTip : function() {
            return this.tip ? this.tip : $(this.options.template);
        },
        detach : function() {
        },
        defaultOptions :{
            title : '',
            content : '',
            direction : 'bottom',
            html : false,
            template : '<div class="tip"><div class="tip-inner"><h3></h3><div class="tip-container"></div></div></div>'
        }
    }
    $.fn.Tip = function(option) {
        return this.each(function(){
            var e = $(this),
                data = e.data('tip'),
                options = typeof option == "object" && option;
            if (!data) e.data("tip", new Tip(this,options));
            if (typeof option == 'string') data[option]();
        });
    }
}(window.jQuery);

.tip {
  position: absolute;
  padding: 3px;
  background: #efefef;
  border-radius: 2px;
  top: 0px;
  left: 0px;
}
.tip .tip-inner {
  background: #fafafb;
  border: 1px solid #d8d8d8;
}
.tip .tip-inner h3 {
  font-size: 14px;
  padding: 5px;
  border-bottom: 1px solid #eee;
}
.tip .tip-inner .tip-container {
  padding: 5px;
}