form.js

	render() {
		return html`
			<section>
				<form id="form-${this._ref}" @submit="${this._login}">
					<label>
						Username:
						<input type="text" name="username">
					</label>
					<label>
						Password:
						<input type="password" name="password">
					</label>
					<button type="submit">Login</button>
				</form>
				</section>
`;
  }
_login(evt) {
		evt.preventDefault();
		const formData = (new FormData(evt.target)).entries();
		let filtered = {};
		for (let pair of formData) {
			filtered[pair[0]] = pair[1].trim();
		}
  // TODO: use filtered
}