toggle_poll_focus.js

// javascript:(function()%20{if%20(window.___focusInterval)%20{clearInterval(window.___focusInterval);delete%20window.___focusInterval;return;}window.___focusInterval%20=%20setInterval(function()%20{console.debug(document.activeElement);}%2C%202000);})();

// Logs the :focus-ed element every few seconds. This can be helpful when
// debugging why the focus is getting lost or is on a visually hidden element.
// Toggles the logging on or off.
(function() {

if (window.___focusInterval) {
	clearInterval(window.___focusInterval);
	delete window.___focusInterval;
	return;
}

window.___focusInterval = setInterval(function() {
	console.debug(document.activeElement);
}, 2000);

})();