mishals

Thank you for this referer & info
But which file edit for add this code ?

function hiddenreferer_shortcode($tag) {

    if ( ! is_array( $tag ) )
        return '';

    $options = (array) $tag['options'];
    foreach ( $options as $option ) {
        if ( preg_match( '%^name:([-0-9a-zA-Z_]+)$%', $option, $matches ) ) {
            $name_att = $matches[1];
        }
    }

     $pageURL = 'http';
     if ($_SERVER["HTTPS"] == "on") {$pageURL .= "s";}
     $pageURL .= "://";
     if ($_SERVER["SERVER_PORT"] != "80") {
          $pageURL .= $_SERVER["SERVER_NAME"].":".$_SERVER["SERVER_PORT"].$_SERVER["REQUEST_URI"];
     } else {
          $pageURL .= $_SERVER["SERVER_NAME"].$_SERVER["REQUEST_URI"];
     }

     $value_att = $pageURL;
     $html = '<input type="hidden" name="' . $name_att . '" value="'.$value_att.'" />';
     return $html;
}
wpcf7_add_shortcode('hiddenreferer', 'hiddenreferer_shortcode', true);