Rails-like number_with_delimiter in javascript
Number.prototype.number_with_delimiter = function(delimiter) {
var number = this + '', delimiter = delimiter || ',';
var split = number.split('.');
split[0] = split[0].replace(
/(\d)(?=(\d\d\d)+(?!\d))/g,
'$1' + delimiter
);
return split.join('.');
};