[转]Javascript 取小数点后面N位
用Javascript取float型小数点后两位，例22.127456取成22.13,如何做？
1. 最笨的办法....... [我就怎么干的.........]
1
function get()
2
{
3
var s = 22.127456 + "";
4 var str = s.substring(0,s.indexOf(".") + 3);
5 alert(str);
6
}
function get()2
{
3
var s = 22.127456 + "";4
var str = s.substring(0,s.indexOf(".") + 3);5
alert(str);6
}
2. 正则表达式效果不错
1<script type="text/javascript">
2onload = function(){
3 var a = "23.456322";
4 var aNew;
5
var re = /([0-9]+\.[0-9]{2})[0-9]*/;
6 aNew = a.replace(re,"$1");
7 alert(aNew);
8}
9</script>
<script type="text/javascript">2
onload = function(){3
var a = "23.456322";4
var aNew;5
var re = /([0-9]+\.[0-9]{2})[0-9]*/;
6
aNew = a.replace(re,"$1");7
alert(aNew);8
}9
</script>
3. 他就比较聪明了.....
1<script>
2var num=22.127456;
3alert( Math.round(num*100)/100);
4</script>
<script>2
var num=22.127456;3
alert( Math.round(num*100)/100);4
</script>
4.会用新鲜东西的朋友....... 但是需要 IE5.5+才支持。
1 <script>
2var num=22.127456;
3alert( num.toFixed(2));
4</script>
<script>2
var num=22.127456;3
alert( num.toFixed(2));4
</script>
来源：http://www.cnblogs.com/wfwup/archive/2009/12/18/1627365.html
