How do I round a number in JavaScript?

Question

While working on a project, I came across a JS-script created by a former employee that basically creates a report in the form of

Name : Value
Name2 : Value2         


        

Answer 1

A very good approximation for rounding:

function Rounding (number, precision){

var newNumber;
var sNumber = number.toString();

var increase = precision + sNumber.length - sNumber.indexOf('.') + 1;

if (number < 0)
  newNumber = (number -  5 * Math.pow(10,-increase));
else
  newNumber = (number +  5 * Math.pow(10,-increase));

var multiple = Math.pow(10,precision);

return Math.round(newNumber * multiple)/multiple;
}

Only in some cases when the length of the decimal part of the number is very long will it be incorrect.