The best you can do with built in JavaScript functions is to round a number to the nearest integer using the method Math.round(x), so to round a float to n decimal points we need to come up with our own function.
The function round_float() rounds a floating point number x to n decimals, if you ommit the parameter n, the function will have the same behaviour as the round() method, here is the round_float function definition:
function round_float(x,n){
if(!parseInt(n))
var n=0;
if(!parseFloat(x))
return false;
return Math.round(x*Math.pow(10,n))/Math.pow(10,n);
}
With prototyping
Dmitry suggested a better approach using prototyping:
if (!Number.toFixed) {
Number.prototype.toFixed=function(n){
return Math.round(this*Math.pow(10, n)) / Math.pow(10, n);
}
}
// example:
floating_number = 123.45687;
decimal_points = 2;
window.alert(floating_number.toFixed(decimal_points));
It would be better to use prototyping here. Newer browsers support toFixed() function. Older don’t.
So here’s the way to do it:
if (!Number.toFixed) { Number.prototype.toFixed=function(x) { var temp=this; temp=Math.round(temp*Math.pow(10,x))/Math.pow(10,x); return temp; }} example: f=123.23453 window.alert(f.toFixed(2));make it simpler
function round(val, prec) { return parseFloat(parseFloat(val).toFixed(prec)); }This is very clean, if val is not a number the function will return NaN (Not a Number)
Thanks Chat!