Edit The Source Of Google Mail Login Page

I have Google Mail login page, saved locally to C: disk. I want to edit its source so, that when entered username and password and clicked on "Login" button it did absolutelly nothing, but the form did not reset. I tried deleting from the source "form action = https"//....", "method = post", "onsubmit = ...".

So, when the form is submitted, nothing happens(as I want it to be), but the field values are reset(what I want to avoid). I also tried inserting to source code "form onsubmit = return false", but the username and password values are still reset.