src/App.php
protected function isJsonRequest()
    {
        $ajax = false;

        if (!empty($_SERVER['HTTP_X_REQUESTED_WITH'])
           && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest') {
            $ajax = true;
        }

        return $ajax && !isset($_GET['__atk_tab']);
    }
protected function isJsonRequest()
    {
        $ajax = false;

        if (!empty($_SERVER['HTTP_X_REQUESTED_WITH'])
           && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest') {
            $ajax = true;
        }

        return $ajax && !isset($_GET['__atk_tab']);
    }
protected function isJsonRequest ( ) { $ ajax = false ; if ( ! empty ( $ _SERVER [ 'HTTP_X_REQUESTED_WITH' ] ) && strtolower ( $ _SERVER [ 'HTTP_X_REQUESTED_WITH' ] ) == 'xmlhttprequest' ) { $ ajax = true ; } return $ ajax && ! isset ( $ _GET [ '__atk_tab' ] ) ; }
Most of the ajax request will require sending exception in json
instead of html, except for tab.

@return bool
Most of the ajax request will require sending exception in json instead of html except for tab .