axe-core/lib/checks/media/frame-tested.js

Accessibility engine for automated Web UI testing

const resolve = this.async();
const { isViolation, timeout } = Object.assign({ isViolation: false, timeout: 500 }, options);

// give the frame .5s to respond to 'axe.ping', else log failed response
let timer = setTimeout(function() {
	// This double timeout is important for allowing iframes to respond
	// DO NOT REMOVE
	timer = setTimeout(function() {
		timer = null;
		resolve(isViolation ? false : undefined);
	}, 0);
}, timeout);

axe.utils.respondable(node.contentWindow, 'axe.ping', null, undefined, function () {
	if (timer !== null) {
		clearTimeout(timer);
		resolve(true);
	}
});