How to make thousand marker in text box

Hi, im wondering how to make a text box with thousand marker.

The textbox is numerical only.

So when people type 4000000 for example,

the textbox will automatically display 4,000,000

Is anyone know how to do that?

Thank you.

 

Code:

<?php

$number = 50000000;

echo number_format($number,0,'.',','); 

?>