Setting Checkbox value to 1 for "Remember Me / Keep me logged in" value

Can I ask what setting the value to 1 actually does when you are using a login form, i know it allows the user to be remembered and not have to login over and over again, and I assume it just sets a cookie in the users browser.
So if i had a checkbox and the value was not set at all, so the static value was totally null, because I forgot to add that in what effect would this have on my login form? would it just ignore if someone clicked the remember me or would it return an error.
And if i assume this is a direct boolean, 1 = true and 0 = false, so when checked it is true to store a cookie in the users browser?
Please just confirm this or give more info if needed.