prevent firefox from filling in the password field in the form for ne…

…w members

if a system user saved their username amd password in their browser,
the browser uses it not only in the login form, but also in other
forms which have a input field of type password. That is the case
in the membership module when creating a new member

in Firefox(tested with Firefox 50.1.0 on Ubuntu 16.10), if only one password
was saved for the site, the email-field is automatically filled with the username
and the password is put in the first password field

with this commit a hidden dummyUserField and dummyPasswdField are added before
the email and password fields. These fields get filled with the username and password,
but it is not visible to the user, because the fields are hidden via css.

unfortunately the solution which was used for chrome (add autocomplete="new-password")
doesn't seem to work in firefox even though there is documentation saying something else:
https://developer.mozilla.org/en-US/docs/Web/Security/Securing_your_site/Turning_off_form_autocompletion
maybe this will be implemented on day and this commit can be reverted

admin/modules/membership/index.php

@@ -507,6 +507,11 @@ function getimagesizefromstring($string_data)
 
     $form->addAnything(__('Photo'), $str_input);
 
+    // hidden username and password fields so that the password manager of the browser will not fill in the username in the memberEmail and the password in the memberPasswd field
+    $form->addTextField('text', 'dummyUserField', null, null, '');
+    $form->addTextField('password', 'dummyPasswdField', null, null, '');
+    echo '<style type="text/css">#simbioFormRowdummyPasswdField, #simbioFormRowdummyUserField {display: none}</style>';
+
     // member email
     $form->addTextField('text', 'memberEmail', __('E-mail'), $rec_d['member_email'], 'style="width: 40%;"');
     // member password