cyberman/public/js/domain_check.js

function checkAvailability() {
	let name = document.getElementById('name').value;
	if (name === '') {
		document.getElementById('avail').innerHTML = '';
		return;
	}
	document.getElementById('avail').innerHTML = 'Checking availability...';
	fetch('/api/check_availability?name=' + encodeURIComponent(name), {
		method: 'GET',
		mode: 'cors'
	}).then(g => g.text()).then(g => {
		if (g === 'y') {
			document.getElementById('avail').innerHTML = 'Available!';
		} else {
			document.getElementById('avail').innerHTML = 'Not available';
		}
	}).catch((e) => {
		document.getElementById('avail').innerHTML = 'Server error';
	});
}