it all depends on what info is required but basically I do something like:
<?
foreach ($_POST as $value) {
if (!$value) {$formfail = true;}
break;
}
if (isset ($formfail)) {echo 'Required fields missing';}
?>
This is a very simplified example. You have to tweak this to exclude non required fields and also remember that checkboxes and radios do not create indexes in $_POST if they are left unchecked so you cannot simply do "if (!$checkbox)", you must do "if (isset ($checkbox))". If you want to get a little fancier, you can add conditional logic to your form to make fields that require user entry to appear in a different color on your validation page.
