My website is almost complete. The very last issue I'm having is
creating a custom field, then making a checkbox show up instead of the
custom field, and the checkbox controls the values of the custom
field, so that if it is clicked, the custom field = "Yes", and if not
clicked cf = "No". I've played around with a multitude of different
combinations of code, but none worked, so I thought maybe you could
help. Here's the code of my latest failed attempt. This will display
in the edit.html.tmpl file:

[% FOREACH field = Bugzilla.active_custom_fields %] - so this
invokes the custom fields
[% IF == 'cf_passtesting' %] -
this singles out the field in question
create input checkbox
value="passtest" -
[% " checked=\"checked\"" IF passtest.checked %]
[% IF passtest.checked == "true" %]
[% cf_passtesting="Yes" %]
[% END %]