js取小數點後幾位

1. 最笨的辦法....... [我就怎麼乾的.........]

function get()

{

    var s = 22.127456 + "";

    var str = s.substring(0,s.indexOf(".") + 3);

    alert(str);

}

2. Regex效果不錯

<script type="text/javascript">

onload = function(){

    var a = "23.456322";

    var aNew;

    var re = /([0-9]+\.[0-9]{2})[0-9]*/;

    aNew = a.replace(re,"$1");

    alert(aNew);

}

</script>

3. 他就比較聰明了.....

<script>

var num=22.127456;

alert( Math.round(num*100)/100);

</script>

4.會用新鮮東西的朋友....... 但是需要 IE5.5+才支援。

 <script>

var num=22.127456;

alert( num.toFixed(2));

</script>

from:http://xinlingwuyu.javaeye.com/blog/175931