封装 鼠标移动事件

js

  var Drag = (function () {
                var $this;

                function drag() {
                    this.ini.apply(this, arguments);
                }
                drag.prototype = {
                    ini:function (inside, outside) {
                        $this = this
                        $this.inside = inside;
                        $this.outside = outside;
                        $this._width=$this.outside.innerWidth()-$this.inside.innerWidth()
                        $this._height=$this.outside.innerHeight()-$this.inside.innerHeight()
                    },
                    position:function (e) {
                        e = e;
                        var x = e.pageX - $this.outside.position().left - $this.inside.innerWidth() / 2
                        var y = e.pageY - $this.outside.position().top - $this.inside.innerHeight() / 2
                        if(x<0){x=0}
                        if(x>$this._width){x=$this._width}
                        if(y<0){y=0}
                        if(y>$this._height){y=$this._height}
                        $this.x = x;
                        $this.y = y;
                        $this.inside.html("x:" + $this.x + "   y:" + $this.y)
                    },
                    move:function () {
                        $this.outside.bind("mousemove", function (e) {
                            $this.position(e)
                            $this.inside.css({"left":$this.x + "px", "top":$this.y + "px" })
                        })

                    }
                }
                return drag;
            }())
            var k = new Drag($(".inside"), $(".outside"))
            k.move()

 html

<div class="outside">
    <div class="inside">
        fgdfg

    </div>

</div>

 css

   .outside {
            position: relative;
            border: 1px solid #FF0;
             700px;
            height: 500px;
        }

        .inside {
            position: absolute;
            border: 1px solid #F00;
             100px;
            height: 100px;

        }

方法很简单，主要试验下js的闭包，模块化设计。