I have been having some issues with duplicate database records being created because sometimes my users will be impatient and click the "Save & Close" multiple times before the processing of the first click has completed. This is easy to duplicate. I did some research and found there are several techniques employed to prevent duplicates, such as:
1. After click disable the Button via Javascript
2. After click disable the Button via jQuery
3. Use form tokens to skip the processing of a submission if the form was already processed.

After experimenting a bit, I have implemented in test mode the 3rd technique, following the approach found here: spotlesswebdesign.com/blog.php?id=11

In my case, I put the following in the view.html.php displayXXX function: (no need to do the session_start()
if (!isset($_SESSION)) {
$_SESSION = array();
}
$_SESSION[] = uniqid('', true);
Then I put this in the form tmplate:
<input type="hidden" name="page_instance_id" value="<?php echo end($_SESSION); ?>" />

And finally, in the controller save() function, I modified the first part of it as follows:

CkJSession::checkToken() or CkJSession::checkToken('get') or jexit(JText::_('JINVALID_TOKEN'));


//Check the ACLs
$model = $this->getModel();
$item = $model->getItem();

$app = JFactory::getApplication();
$data = $app->input->post->get('jform', array(), 'array');
//rbn - prevent duplicate form submissions
$page_id_index = array_search($_POST, $_SESSION);
if ($page_id_index !== false) {

unset($_SESSION[$page_id_index]);


$result = false;
if ($model->canEdit($item, true))
{
$result = parent::save();
//Get the model through postSaveHook()
if ($this->model)
{
$model = $this->model;
$item = $model->getItem();
}
}
else
JError::raiseWarning( 403, JText::sprintf('ACL_UNAUTORIZED_TASK', JText::_('VOLUNTEER_JTOOLBAR_SAVE')) );

$this->_result = $result;

}


This seems to work but I would appreciate input on the following:

1. Is there any easier/simpler approach (must modify/fork three files for this solution).
2. Do you see where this could cause any unintended problems or interactions elsewhere?

Thanks