Format numbers in javascript

Format numbers in javascript same in C#


Here's a simple JS function to add commas to an integer number in string format.

function addCommas(str) {
    var amount = new String(str);
    amount = amount.split("").reverse();

    var output = "";
    for ( var i = 0; i <= amount.length-1; i++ ){
        output = amount[i] + output;
        if ((i+1) % 3 == 0 && (amount.length-1) !== i)output = ',' + output;
    }
    return output;
}

example:

addCommas(12345);

output: 12,345