@armins
that works perfect !! thanks

this is the line ..
<input type="button" class="button" name="btn_download" value="Download" onClick="if (!$('isys_form').down('[name="download"]').getValue().blank()) {$('isys_form').submit();}" />

after updating to 1.12.2 the update procedure from 1.12.2. to 1.12.3 stops at the download button

ont the i-doit update i see the message "new version available " but clicking on the button the browser do nothing , checking on the debug window of my chrome i see an error :
Uncaught SyntaxError: Invalid or unexpected token index.php:77 /