MODx 2 Plugin OnBeforeDocFormSave

Here is an example to make a tv to be a required field:

----------------------

<?php

/*

* $mode: "new/upd"

* $resource: modResource object

* $id: resource id

* @ref http://rtfm.modx.com/display/revolution20/OnBeforeDocFormSave

* Calling $modx->event->output("..."); will output error and cancel save

*/

if (empty($_REQUEST["tv4"])) {

$modx->event->output("Field 'XXX' is required");

}