DO NOT USE THIS, IT HAS A BUG. Keeping it for illustration purposes. A little thing I knocked up to safely scale a javascript number using strings to avoid floating point issues. The bug is where the multipleOfTenAsNumber has more digits than the original number. It doesn't work in that case. E.g. console.log(safeScale("109.87654",10000000000));…

safeScale.js

// if you try this in javascript: 
// 10.2 * 100
// you get this:
// 1019.9999999999999
/** Safely scale a number. Just a hacky little demo.
 * @param {string} numberAsString the number you want to scale e.g. 10.987654
 * @param {number} multipleOfTenAsNumber the number you want to scale by e.g. 1000
 * @returns {safeScale.result} the safely scaled number e.g. 10987.654
 */ 
function safeScale(numberAsString, multipleOfTenAsNumber) {
    var numberParts, result, numZerosInMultipleOfTen;
    numZerosInMultipleOfTen = Math.round(Math.log(multipleOfTenAsNumber) / Math.log(10)); // e.g. for multipleOfTenAsNumber=1000, will return 3
    numberParts = numberAsString.split(".");
    result = Number(numberParts[0]) * multipleOfTenAsNumber ; // integer calculation
    result += Number(numberParts[1].substr(0, numZerosInMultipleOfTen) ); // add the rest of the whole part
    result += Number("0." + numberParts[1].substr(numZerosInMultipleOfTen)); // add the fractional part.
    return result;
}
//console.log(safeScale("10.20",100));
// 1020 
//console.log(safeScale("10987.654",1000));