nextcloud-server/core/js/login/authpicker.js

jQuery(document).ready(function() {
	$('#app-token-login').click(function (e) {
		e.preventDefault();
		$(this).addClass('hidden');
		$('#redirect-link').addClass('hidden');
		$('#app-token-login-field').removeClass('hidden');
	});

	document.getElementById('login-form').addEventListener('submit', function (e) {
		e.preventDefault();
		document.location.href = e.target.attributes.action.value
	})
})