Before page loads form =get

I have a page called notifications here all notifications are displaying thru db!
Notifications columns are: ID, UserId, SenderId, TimeAdded, UnRead & JobiD.

All values are added except unread = 0.
I want to turn this value to 1 as user clicks on the notification. As he clicks he is taken to a job details page about the notification & other details.

Now on details page i used link like this: ../job-details.php?JobID=213&NotificationID=5 (This means the person has clicked on notification which ID is 5 & JobID is 213 which currently is displaying details on JobID=213. As as person visits this page i have made a form in job-details.php page as :

<form name="notifications" action="job-details.php" method="post">
           <input name="NotificationID" type="hidden" value="<?php echo((isset($_GET["NotificationID"]))?$_GET["NotificationID"]:"") ?>" />
       </form>

I added update record server variable here using data assist As NotificationID as key value for table Notifications & setting trigger as before page loads & in binding choosing UnRead as 1 as value. But it doesnt work. But if a add a submit button & change trigger to on submit then it doesnt work.

How to make this work on Before page load?