myInteger.ToString("N0")
Example: 10000000.2345 -> '1,000,000.2345'
function numberWithCommas(x) {
var parts = x.toString().split(".");
parts[0] = parts[0].replace(/B(?=(d{3})+(?!d))/g, ",");
return parts.join(".");
}
>>> '{:,}'.format(1234567890)
'1,234,567,890'