how to apply masked input plug-in to a password field?

I am trying to apply masked input plugin ( jquery.maskedinput.min.js ) to a password field in order to create :

****-****-****

It is basically a registration key separated by dashes.

 $(document).ready(function(){
        $("#registrationKey").mask("9999-9999-9999");

        $("#registrationKey").keyup(function(e) {
              self = $(this);
              rkValue = self.val().replace(/[^d-]/g, '');
              self.val(rkValue);
              console.log("value = " + rkValue);
              self.attr("regKey", rkValue);
        });
});

<input type="password" id="registrationKey" name="registrationKey" regKey="" maxlength="15" autocomplete="off" >

I am having 2 problems. First one is that the field is already populated due to mask being applied. Second problem is it won't apply a dash after every 4th digit.

Is there a way to accomplish this via pure javascript or via this plug-in?

By the way, I have seen something similar in another post. However, it is very buggy if a user places the mouse in the middle of the field, or highlights some section of the text and deletes it.

Any ideas?

thanks