Including a hyphen in a regex character bracket?

$.validator.addMethod('AZ09_', function (value) { 
    return /^[a-zA-Z0-9.-_]+$/.test(value); 
}, 'Only letters, numbers, and _-. are allowed');

When I use somehting like test-123 it still triggers as if the hyphen is invalid. I tried - and --


Escaping using - should be fine, but you can also try putting it at the beginning or the end of the character class. This should work for you: