[Javascript] Round a number to a specified decimal place

gistfile1.js

/**
 * Round a number to a specified decimal place.
 * @var num The number to be rounded
 * @var digits The digit behind the decimal point to be rounded to
 */

function roundNumber(num, digits) {
    num = parserFloat(num);
    var multiple = Math.pow(10, digits);
    return Math.round(num * multiple) / multiple;
}​