html:

<form action="account/edit">....</form>

javascript:

$('form[action="account/edit"]').size();
$('form[action="account/edit"]').attr('action');
$('form[action="http://example.org/account/edit"]').size();
$('form[action="http://example.org/account/edit"]').attr('action');

results:

firefox-1.5.0.1, firefox-2.0.0.13, firefox-3b5: 0, "undefined", 1, "account/edit"
mozilla-1.7.7, opera-9.50b, ie-6, ie-7, safari-3.1.525.13: 1, "account/edit", 0, "undefined"
opera-8.0, opera-9.00, opera-9.26: 0, "undefined", 1, "http://example.org/account/edit"

conclusions:

- the firefoxes differ
- jquery should hide these browser incompatibilities and always result in: 1, "account/edit", 0, "undefined"