In Javascript, I've had loops set up where it asks the user to input a number and then using isNaN(), it determines if they input the correct information and if not, loops back to the beginning.

This is great for doing math and stuff, but what if I want names? So that if the user enters numbers, I get a false result and it continues in the loop. I've done some searching, but I can't find anything for it. Is this possible?