js鼠标滚轴控制文本框值

[javascript]
<html>

<head>

<title></title>
<script type="text/javascript" language="javascript">

    /*根据获得焦点的时候给setVal给值*/
    var setVal;
    var bool = false;
    var scrollFunc=function(e){
        var direct=0;
        e=e || window.event;
        var ew = e.wheelDelta
        if(ew && bool){
            if(ew > 0){
                var num1 = setVal.value;
                if(num1 > 0){
                    num1 = eval(1+parseInt(num1));
                }else{
                    num1 = 1;
                }
            }else{
                var num1 = setVal.value;
                if(num1 > 0){
                    num1 = eval(parseInt(num1)-1);
                }else if(num1 == 0){
                    num1 = 0;
                }else{
                    num1 = 1;
                }
            }

            setVal.value = num1;
        }

    }

    window.onmousewheel=document.onmousewheel=scrollFunc;

    function ufocus(eve){
        bool = true;
        setVal = eve;
    }

    function ublur(){
        bool = false;
        setVal = null;
    }
</script>
</head>

<body>
<input type="text" onfocus="ufocus(this)" onblur="ublur(this)"/>
</body>

</html>

<html>

<head>

<title></title>
<script type="text/javascript" language="javascript">

    /*根据获得焦点的时候给setVal给值*/
    var setVal;
    var bool = false;
    var scrollFunc=function(e){
        var direct=0;
        e=e || window.event;
        var ew = e.wheelDelta
        if(ew && bool){
            if(ew > 0){
                var num1 = setVal.value;
                if(num1 > 0){
                    num1 = eval(1+parseInt(num1));
                }else{
                    num1 = 1;
                }
            }else{
                var num1 = setVal.value;
                if(num1 > 0){
                    num1 = eval(parseInt(num1)-1);
                }else if(num1 == 0){
                    num1 = 0;
                }else{
                    num1 = 1;
                }
            }

            setVal.value = num1;
        }

    }

    window.onmousewheel=document.onmousewheel=scrollFunc;

    function ufocus(eve){
        bool = true;
        setVal = eve;
    }

    function ublur(){
        bool = false;
        setVal = null;
    }
</script>
</head>

</html>

补充：web前端 , JavaScript ,