Commas messing with number input in Javascript

Question

I have a page with some elements that are controlled by the user. One of these is a text input field, where the user is supposed to input a number. Everything works well if

Answer 1

Or even better, given the general unreliability of user input, use this to get rid of all non-numeric characters:

var s = "9,Ljk876";
var t = parseInt(s.replace(/[^0-9]/g, ''));
alert ("s:" + s + ", t:" + t);