Waiting element exists

waiting.js

function avocaWaitForElm(selector) {
	return new Promise(resolve => {
		if (document.querySelector(selector)) {
			return resolve(document.querySelector(selector));
		}

		const observer = new MutationObserver(mutations => {
			if (document.querySelector(selector)) {
				resolve(document.querySelector(selector));
				observer.disconnect();
			}
		});

		observer.observe(document.body, {
			childList: true,
			subtree: true
		});
	});
}

avocaWaitForElm('input[name="mf-date-cs').then((elm) => {
    console.log('Element is ready');
    console.log(elm.textContent);
});