JavaScript decimal rounding a variety of methods to achieve the basic knowledge

Use JavaScript to take float type two digits after the decimal point, example 22.127456 to 22.13, how to do?
1. The Dumbest way

Copy Code code as follows:

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

2. Regular expression works well

Copy Code code as follows:

<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, "$");
alert (anew);
}
</script>

3. He's smarter ......

Copy Code code as follows:

<script>
var num=22.127456;
Alert (Math.Round (num*100)/100);
</script>

4. Friends who will use new things....... But it takes ie5.5+ to support it.

Copy Code code as follows:

<script>
var num=22.127456;
Alert (num.tofixed (2));
</script>