Run command on enter push

I dont know if im not looking in the correct areas, but I cant seem to find
the answer to my question. All I want is to run a command when the enter key
on the keyboard is pushed. I have a form with two fields and a button. User
name, and password are the fields. Login is the button. I would like the
login button event to happen if the user pushes enter on the keyboard while
on the password field. Is this possible?
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