Form form upload image-submitted to the PHP method, after successful want to return some values, but the foreground is always unable to get the parameter value. Urgent!!!

PHP picture Form Upload

form part code: To implement the form submission page does not jump.

Php Method: Image upload success or failure, want to return the image of the path and error messages. The pass-through method is as follows
$cardnoimg = $destination _folder; --Picture path
$smarty->assign (' cardnoimg ', $cardnoimg); --Incoming DWT template page
$smarty->assign (' mag ', $mag); --Error message incoming DWT template page
Now there are two problems.
1: I want to use JS to get the picture path, and assign a value to a hidden text box. So where should this approach be written? Isn't it appropriate to write in the OnSubmit method of the form?
2: That is how I write PHP to let the DWT template read these values?
I am a rookie, please the great God detailed description.

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