customize error popup

[redtick]

Hello; I'm new to prestashop

i'm trying to replace an error alert with popup window

the error alert exist on category.php page when i add a product to basket without login

 

i get this alert 

 

from CartController (the code

 

if (Tools::getValue('ajax') === 'true' && Tools::getValue('add') === '1') { // ajax cart

        die('{"hasError" : true, "errors" : ["' . Tools::displayError('Please login first .', false) . '"]}');

      }

 

so I was trying to create the popup on category.tpl and put visibility:hidden;

 

But how can I manage the popup  visibility from CartController !!

Edited April 18, 2014 by redtick (see edit history)