用js取float型小数点后两位 （四舍五入）

<input  type="text"  name='text' id='text'

  onkeyup="javascript: var myreg=/^[+]?(([1-9]\d*[.]?)|(0.))(\d{0,2})?$/;if(!myreg.test(this.value)){this.value=''; }; "   />

//  ie    js

function controlValue(){
    var reg=/^[+]?(([1-9]\d*[.]?)|(0.))(\d{0,2})?$/;
    var value = event.srcElement.value;
    if(!reg.test(value))
      event.srcElement.value= "";
}

 

1. 最笨的办法....... [我就怎么干的.........]

function get()
{
var s = 22.127456 + "";
var str = s.substring(0,s.indexOf(".") + 3);
alert(str);
}

2. 正则 效果不错

<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. 他就比较聪明了.....

<script>
var num=22.127456;
alert( Math.round(num*100)/100);
</script>

4.会用新鲜东西的朋友.......

<script>
var num=22.127456;
alert( num.toFixed(2));
</script>