jquery实现拖拽进度条并显示百分比的特效

#box{position: relative; width: 200px; height: 50px; border: 1px solid #eee; margin: 50px auto 0;}
#bg{height: 10px; margin-top: 19px; border: 1px solid #ddd; border-radius: 5px; overflow: hidden;}
#bgcolor{background: #5889B2; width: 0; height: 10px; border-radius: 5px;}
#bt{width: 34px; height: 34px; background: url(http://bbs.blueidea.com/data/attachment/album/201505/22/192934pwywwrt8cbrfwzfh.png) no-repeat center center; border-radius: 17px; overflow: hidden; position: absolute; left: 0px; margin-left: -17px; top: 8px; cursor: pointer;}
#text{width: 200px; margin: 0 auto; font-size: 16px; line-height: 2em;}

<div id="box">
    <div id="bg">
        <div id="bgcolor"></div>
    </div>
    <div id="bt"></div>
</div>
<div id="text"></div>

(function($){
    var $box = $('#box');
    var $bg = $('#bg');
    var $bgcolor = $('#bgcolor');
    var $btn = $('#bt');
    var $text = $('#text');
    var statu = false;
    var ox = 0;
    var lx = 0;
    var left = 0;
    var bgleft = 0;
    $btn.mousedown(function(e){
        console.log(0)
        lx = $btn.offset().left;
        ox = e.pageX - left;
        statu = true;
    });
$(document).mouseup(function(){
    statu = false;
});
$box.mousemove(function(e){
    console.log(1)
    if(statu){
        left = e.pageX - ox;
        if(left < 0){
            left = 0;
        }
        if(left > 200){
             left = 200;
        }
        $btn.css('left',left);
        $bgcolor.width(left);
        $text.html('位置:' + parseInt(left/2) + '%');
    }
});

$bg.click(function(e){
    console.log(2)
    if(!statu){
    bgleft = $bg.offset().left;
    left = e.pageX - bgleft;
    if(left < 0){
        left = 0;
    }
    if(left > 200){
        left = 200;
    }
    $btn.css('left',left);
    $bgcolor.stop().animate({left},200);
    $text.html('位置:' + parseInt(left/2) + '%');
}
});
})(jQuery);