进度条（可拖动，可定义）

在工作中，有一个进度条的效果，左边是一个input，两者存在着密不可分的联系，引用的插件却出现了点小BUG，一怒之下自己写了一个。

HTML

    <div>
        <input type="text" id="input" value="" placeholder="0" autocomplete="off">%
        <div id="tiao">
            <div id="yuan"></div>
            <div id="jindu"></div>
        </div>
    </div>

CSS

    html,body{
            height: 100%;
        }
        body{
            margin: 0;
        }
        body>div{
            padding-top: 60px;
            margin-left: 60px;
        }
        #tiao{
            display: inline-block;
            width: 200px;
            height: 4px;
            background: #ddd;
            border-radius: 3px;
            position: relative;
            margin-left: 50px;
        }
        input{
            border: 1px solid #ddd;
            width: 100px;
            text-align: center;
            vertical-align: top;
        }
        #yuan{
            display: inline-block;
            width: 12px;
            height: 12px;
            border-radius: 50% 50%;
            background: #177ad8;
            position: absolute;
            margin-top: -4px;
            cursor: pointer;
            box-shadow: 0px 0px 3px #177ad8;
        }
        #jindu{
            width: 0px;
            height: 4px;
            background-color: #177ad8;
            border-radius: 3px;
        }

    var scale =function(input,yuan,jindu,tiao){
        this.input =document.getElementById(input);
        this.yuan =document.getElementById(yuan);
        this.jindu=document.getElementById(jindu);
        this.tiao=document.getElementById(tiao);
        this.tiaoW =this.tiao.offsetWidth;
        this.init()
    }
    scale.prototype ={
        init: function(){
            var isfalse =false, 
                f = this,
                m = Math,
                b = document.body,
                minValue =0,
                maxValue =100;
            
            f.yuan.onmousedown =function(e){
                isfalse =true;
                var X =e.clientX;
                var offleft =this.offsetLeft;
                var max = f.tiao.offsetWidth - this.offsetWidth;

                b.onmousemove =function(e){
                    if (isfalse == false){
                        return;
                    }
                    var changeX= e.clientX;
                    var moveX =m.min(max,m.max(-2,offleft+(changeX-X)));
                    f.input.value =m.round(m.max(0,moveX / max) * 100);
                    f.yuan.style.marginLeft =m.max(0, moveX) +"px";
                    f.jindu.style.width =moveX +"px";
                }
            }
            b.onmouseup =function(){
                isfalse =false;
            }

            f.input.onblur =function(){
                var theV =this.value*1;
                if(theV >maxValue || theV <minValue){
                    alert("输入的数值不正确");
                    f.input.value ="";
                    f.yuan.style.marginLeft ="0px";
                    f.jindu.style.width ="0px";
                    return;
                }
                var xxx =theV/100*f.tiaoW;
                f.yuan.style.marginLeft =xxx +"px";
                f.jindu.style.width =xxx +"px";
            }
        }
    }

    new scale("input","yuan","jindu","tiao");

封装了一下，感觉更麻烦了。。。每次封装都有这样的感觉，毕竟小菜鸟一枚，若是有更优化的方法望看到的园友指正。。。

关于数学，关于逻辑，都是我的弱势，思考起来常常脑海一片混乱，所以自己在编写的时候也会加上注释，放一波代码

    var input =document.getElementById("input");
    var yuan =document.getElementById("yuan");
    var jindu =document.getElementById("jindu");
    var tiao =document.getElementById("tiao");
    var tiaoW =tiao.offsetWidth;

    function schedule(){

        var isfalse =false; //控制滑动

        yuan.onmousedown =function(e){
            isfalse =true;

            var X =e.clientX; //获取当前元素相对于窗口的X左边
            
            var offleft =this.offsetLeft; //当前元素相对于父元素的左边距
            
            var max = tiao.offsetWidth - this.offsetWidth; //宽度的差值
            
            document.body.onmousemove=function(e){
                if (isfalse == false){
                    return;
                }
                var changeX= e.clientX; //在移动的时候获取X坐标
                
                var moveX =Math.min(max,Math.max(-2,offleft+(changeX-X))); //超过总宽度取最大宽
                input.value =Math.round(Math.max(0,moveX / max) * 100);
                yuan.style.marginLeft =Math.max(0, moveX) +"px";
                jindu.style.width =moveX +"px";
            }
        }
        document.body.onmouseup =function(){
            isfalse =false; 
        }

        var minValue =0;
        var maxValue =100;
        input.onblur =function(){
            var theV =this.value*1;
            if(theV >maxValue || theV <minValue){
                alert("输入的数值不正确");
                input.value ="";
                jindu.style.width ="0px";
                yuan.style.marginLeft ="0px";
                return;
            }
            var xxx =theV/100*tiaoW;
            yuan.style.marginLeft =xxx +"px";
            jindu.style.width =xxx +"px";
        }
    }
    schedule();

这个看起来易懂点。。。点击这里看效果