_opera-xdr-engine.js

/**
 * Register event listener for XDR
 *
 */
window.opera.addEventListener('BeforeScript', function(e) {
            if (!e.element._callback) {
                return true;
            }

            e.element._callback.call(window, e.element.text);
            e.preventDefault();
            e.stopPropagation();
        }, true);