Bug 9783 - can hit submit twice when adding patrons

Bug 9783 - can hit submit twice when adding patrons

Currently, clicking twice or more on the Save button will generate
duplicate patrons when adding patrons in the Patron module. Of course,
there is handling that detects this, so you can choose to either edit
the original record (i.e. throw away the duplicate) or create a
duplicate record.

However, it shouldn't get to that point by clicking on the Save button.
That handling seems to be there to handle cases where you go through the
whole process of trying to add a new patron only to find out that they
already exist in the system (or at least their username/password do).

--

This patch uses the "preventDoubleFormSubmit" function (which is also
used in holds and fines to prevent double form submits). It was also
necessary to edit members.js, since "check_form_borrowers" was forcing
form submits despite the "preventDoubleFormSubmit" function. I've
changed it from forcing a document.form.submit to return true, which the
browser will still submit the form if it's a unique borrower, but the
"preventDoubleFormSubmit" function will still prevent multiple submits.

I've also added a "waiting" class to staff-global.js which changes the
cursor to "wait" (i.e. loading circle graphic). I've included an
"AddClass" call in "preventDoubleFormSubmit", so that the cursor graphic
will change to show users that the page is loading so that they don't
click Save again. Of course, even if they do click save again, there
will only be one submit. However, this way - as Chris Cormack mentioned
- the user knows that "something" is happening and that the form isn't
broken.

-------
Test Plan

Before applying patch...

1) Fill out the form for a new patron in the Patron module
2) Click "Save" several times
3) Once the page loads, you'll be shown a prompt that says that this
   borrower already exists. You will have the option to view the
   original record, edit the original record, or create a new patron
   anyway
4) Click on edit the existing record, and delete the patron

Apply the patch

5) Repeat steps 1 and 2
6) Notice that your cursor has changed into a little "loading" circle
   graphic when you hover over the "body" of the page, as well as any
   links or any inputs/buttons of the type "submit" within that form
7) Notice that no matter how many times you press the button, the form
   is not re-submitted. Eventually you will be taken to the new patron's
   record (no mention of duplication will occur)

Ta da! Multiple form submits are prevented and the loading graphic
signals to users that the form was submitted and that Koha is processing
their data

--

I understand that some people might want to change which elements are
given the "waiting" class. I'm happy to renegotiate this as necessary.

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Looks good and works nicely.
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>