Ok, so I'm trying to stick to the following password rule:
Must be between 6 and 15 characters, include at least one lowercase letter, one uppercase letter, and at least one number. It should also not contain spaces.
Now, for everything except spaces, I have:
^(?=.*[a-z])(?=.*[A-Z])(?=.*\d).{6,15}$
The problem is that spaces are allowed.
After inspection, I tried to use \s, but it ruined my lowercase and capital requirements. I also saw another offer to replace *with +, but that seemed to break the whole thing.
I created a REFiddle if you want to do a live test.
To clarify, unfortunately, this is a requirement of the client, I never happen so strictly with passwords.