test

        var errBox = document.getElementById('login-error');

        var btn = document.getElementById('login-btn');

        // Derive the mount prefix from the current location so login works both

        // at the domain root and behind a proxy prefix (e.g. /editor). Strips a

        // trailing slash and an optional /login or /login.html suffix.

        var basePath = window.location.pathname

            .replace(/\/(login|login\.html|index\.html)?$/, '');

        form.addEventListener('submit', function(e) {

            e.preventDefault();

            errBox.style.display = 'none';

            btn.textContent = I18n.t('Loading...', 'Signing in...');

            var xhr = new XMLHttpRequest();

            xhr.open('POST', '/api/login', true);

            xhr.open('POST', basePath + '/api/login', true);

            xhr.setRequestHeader('Content-Type', 'application/json');

            xhr.onreadystatechange = function() {

                if (xhr.readyState !== 4) return;

                btn.textContent = I18n.t('Submit', 'Sign in');

                if (xhr.status === 200) {

                    window.location.href = '/';

                    window.location.href = basePath + '/';

                } else {

                    try {

                        var resp = JSON.parse(xhr.responseText);