Load A Page And Prefill Form Field

The online banking site I use has autofill=no set in their login form,
and I recently switched from IE to Safari, which honors this. I'd like
my account number to be filled in automatically like IE did (please, no
comments on whether this is a good idea or not, I've already had this
discussion in another group and I've decided the account number is not
something I consider a big secret, since it's visible on every check --
that's what the PIN is for).

I'm trying to do this with a bookmarklet. The following works to fill
in the account number and move focus to the PIN field:

document.Login.userNumber.value=﾿?'
document.Login.password.focus()

(newlines included to make the post easier to read, they're not in the
actual bookmarklet).

But this requires me to use two bookmarks, a regular one to load the
site, and this one to fill in the field. I'd like a single bookmarklet
that does both steps at once. I tried:

window.location='https://www.directib.com/onlineserv/HB/Signon.cgi'
document.Login.userNumber.value=﾿?'
document.Login.password.focus()

What am I missing?