Programming :: Javascript Many Characters As Reg Expression Replace?

I'm working with javascript and trying to replace all instances of a Roman character in a string with nothing. How do I assign var reg to all Roman characters? In UTF8, capital letter A is U0041 and at the other end, small z is UFF5A.

So, I'd like to do something like:
var reg = u0041 - UFF5A;
str1 = str.replace(reg, '');

I think you get the idea. I have no idea if that can be done. The idea is to take this string (for example): str = make a door-to-door[house-to-house] visit / ring every doorbell." And take out all the Roman characters and define it as str1. And then take out all the Korean characters (u1100-uFFDC) and define it as str2. In fact, a WAY more useful thing to do would be to replace the instance of this: [u1100-uFFDC]+" "+[u0041-UFF5A] with [u1100-uFFDC]+","+[u0041-UFF5A] so that the output would be a .csv file.