js或jquery 即时加减吗？解决方案 _JavaScript

js或jquery 即时加减吗？
在文本框左边放一加号右边放一个减号，点击加号数值加1（或0.5）点击减号减1（或0.5），文本框的初始值是零
具体效果像这个网页：http://www.codefans.net/jscss/code/2430.shtml 谢谢各位了。

------解决方案--------------------
你发的那个链接稍微改下不就行了，不会改吗。。

HTML code

<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>无标题文档</title>
</head>

<body>
    <span id="add">+</span>
    <input type="text" value="0" id="text"/>
    <span id="reduce">-</span>
    <script>
        function $(id){
            return document.getElementById(id);
        }
        var elems = {
            add: $('add'),
            reduce: $('reduce'),
            text: $('text')
        }
        elems.add.onclick = function(){
            elems.text.value++;
        }
        elems.reduce.onclick = function(){
            elems.text.value--;
        }
    </script>
</body>
</html>

------解决方案--------------------

HTML code<html>
<head>
    <title></title>
    <style type="text/css">
        span
        {
            border: 1px solid gray;
            cursor: pointer;
            color: Gray;
            height: 2px;
            width: 2px;
        }
    </style>
    <script type="text/javascript">
        function autoPlusMinus() {
            var operator = event.srcElement.innerText;
            if (operator != "+" && operator != "-") {
                return;
            }
            var oldValue = number.value;
            if (isNaN(oldValue)) {
                number.value = "0";
            }
            oldValue = parseFloat(number.value);
            number.value = eval(oldValue + operator + 1).toString();
        }
        document.onclick = autoPlusMinus;
    </script>
</head>
<body>
    <span id="plus">+</span>&nbsp;<input id="number" type="text" value="0" style="width: 40px;
        text-align: center;" />&nbsp;<span id="minus">-</span>
</body>
</html>