diff --git a/js/src/ajax.js b/js/src/ajax.js
new file mode 100644
index 0000000..8c615fe
--- /dev/null
+++ b/js/src/ajax.js
@@ -0,0 +1,111 @@
+/*
+ * μlogger
+ *
+ * Copyright(C) 2019 Bartek Fabiszewski (www.fabiszewski.net)
+ *
+ * This is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+export default class uAjax {
+
+  /**
+   * Perform POST HTTP request
+   * @alias ajax
+   */
+  static post(url, data, options) {
+    const params = options || {};
+    params.method = 'POST';
+    return this.ajax(url, data, params);
+  }
+
+  /**
+   * Perform GET HTTP request
+   * @alias ajax
+   */
+  static get(url, data, options) {
+    const params = options || {};
+    params.method = 'GET';
+    return this.ajax(url, data, params);
+  }
+
+  /**
+   * Perform ajax HTTP request
+   * @param {string} url Request URL
+   * @param {Object|HTMLFormElement} [data] Optional request parameters: key/value pairs or form element
+   * @param {Object} [options] Optional options
+   * @param {string} [options.method='GET'] Optional query method, default 'GET'
+   * @return {Promise<Object, string>}
+   */
+  static ajax(url, data, options) {
+    const params = [];
+    data = data || {};
+    options = options || {};
+    const method = options.method || 'GET';
+    const xhr = new XMLHttpRequest();
+    return new Promise((resolve, reject) => {
+      xhr.onreadystatechange = function () {
+        if (xhr.readyState !== XMLHttpRequest.DONE) { return; }
+        let message = '';
+        let error = true;
+        if (xhr.status === 200) {
+          try {
+            const obj = JSON.parse(xhr.responseText);
+            if (obj) {
+              if (!obj.error) {
+                if (resolve && typeof resolve === 'function') {
+                  resolve(obj);
+                }
+                error = false;
+              } else if (obj.message) {
+                  message = obj.message;
+              }
+            }
+          } catch (err) {
+            message = err.message;
+          }
+        } else {
+          message = `HTTP error ${xhr.status}`;
+        }
+        if (error && reject && typeof reject === 'function') {
+          reject(message);
+        }
+      };
+      let body = null;
+      if (data instanceof HTMLFormElement) {
+        if (method === 'POST') {
+          body = new FormData(data);
+        } else {
+          body = new URLSearchParams(new FormData(data)).toString();
+        }
+      } else {
+        for (const key in data) {
+          if (data.hasOwnProperty(key)) {
+            params.push(key + '=' + encodeURIComponent(data[key]));
+          }
+        }
+        body = params.join('&');
+        body = body.replace(/%20/g, '+');
+      }
+      if (method === 'GET' && body.length) {
+        url += '?' + body;
+        body = null;
+      }
+      xhr.open(method, url, true);
+      if (method === 'POST' && !(data instanceof HTMLFormElement)) {
+        xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
+      }
+      xhr.send(body);
+    });
+  }
+}
diff --git a/js/test/ajax.test.js b/js/test/ajax.test.js
new file mode 100644
index 0000000..17f7450
--- /dev/null
+++ b/js/test/ajax.test.js
@@ -0,0 +1,157 @@
+/*
+ * μlogger
+ *
+ * Copyright(C) 2019 Bartek Fabiszewski (www.fabiszewski.net)
+ *
+ * This is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+import uAjax from '../src/ajax.js';
+
+describe('Ajax tests', () => {
+
+  const url = 'http://ulogger.test/';
+  const validResponse = { id: 1 };
+  const invalidResponse = 'invalid';
+  const errorResponse = { error: true, message: 'response error' };
+  const form = document.createElement('form');
+  const input = document.createElement('input');
+  input.type = 'text';
+  input.name = 'p1';
+  input.value = 'test';
+  form.appendChild(input);
+
+  beforeEach(() => {
+    spyOn(XMLHttpRequest.prototype, 'open').and.callThrough();
+    spyOn(XMLHttpRequest.prototype, 'setRequestHeader').and.callThrough();
+    spyOn(XMLHttpRequest.prototype, 'send');
+    spyOnProperty(XMLHttpRequest.prototype, 'readyState').and.returnValue(XMLHttpRequest.DONE);
+  });
+
+  it('should make POST request', () => {
+    // when
+    uAjax.post(url);
+    // then
+    expect(XMLHttpRequest.prototype.setRequestHeader).toHaveBeenCalledWith('Content-type', 'application/x-www-form-urlencoded');
+    expect(XMLHttpRequest.prototype.open).toHaveBeenCalledWith('POST', url, true);
+  });
+
+  it('should make GET request', () => {
+    // when
+    uAjax.get(url);
+    // then
+    expect(XMLHttpRequest.prototype.setRequestHeader).not.toHaveBeenCalled();
+    expect(XMLHttpRequest.prototype.open).toHaveBeenCalledWith('GET', url, true);
+  });
+
+  it('should make GET request with parameters', () => {
+    // when
+    uAjax.get(url, { p1: 1, p2: 'test' });
+    // then
+    expect(XMLHttpRequest.prototype.open).toHaveBeenCalledWith('GET', `${url}?p1=1&p2=test`, true);
+    expect(XMLHttpRequest.prototype.send).toHaveBeenCalledWith(null);
+  });
+
+  it('should make POST request with parameters', () => {
+    // when
+    uAjax.post(url, { p1: 1, p2: 'test' });
+    // then
+    expect(XMLHttpRequest.prototype.open).toHaveBeenCalledWith('POST', url, true);
+    expect(XMLHttpRequest.prototype.send).toHaveBeenCalledWith('p1=1&p2=test');
+  });
+
+  it('should make POST request with form data', () => {
+    // when
+    uAjax.post(url, form);
+    // then
+    expect(XMLHttpRequest.prototype.setRequestHeader).not.toHaveBeenCalled();
+    expect(XMLHttpRequest.prototype.open).toHaveBeenCalledWith('POST', url, true);
+    expect(XMLHttpRequest.prototype.send).toHaveBeenCalledWith(new FormData(form));
+  });
+
+  it('should make GET request with form data', () => {
+    // when
+    uAjax.get(url, form);
+    // then
+    expect(XMLHttpRequest.prototype.setRequestHeader).not.toHaveBeenCalled();
+    expect(XMLHttpRequest.prototype.open).toHaveBeenCalledWith('GET', `${url}?p1=test`, true);
+    expect(XMLHttpRequest.prototype.send).toHaveBeenCalledWith(null);
+  });
+
+  it('should make successful request and return value', (done) => {
+    // when
+    spyOnProperty(XMLHttpRequest.prototype, 'status').and.returnValue(200);
+    spyOnProperty(XMLHttpRequest.prototype, 'responseText').and.returnValue(JSON.stringify(validResponse));
+    // then
+    uAjax.get(url)
+      .then((result) => {
+      expect(result).toEqual(validResponse);
+      done();
+    })
+      .catch(() => done.fail('reject callback called'));
+  });
+
+  it('should make successful request and return error with message', (done) => {
+    // when
+    spyOnProperty(XMLHttpRequest.prototype, 'status').and.returnValue(200);
+    spyOnProperty(XMLHttpRequest.prototype, 'responseText').and.returnValue(JSON.stringify(errorResponse));
+    // then
+    uAjax.get(url)
+      .then(() => done.fail('resolve callback called'))
+      .catch((message) => {
+        expect(message).toBe(errorResponse.message);
+        done();
+      });
+  });
+
+  it('should make successful request and return error without message', (done) => {
+    // when
+    spyOnProperty(XMLHttpRequest.prototype, 'status').and.returnValue(200);
+    spyOnProperty(XMLHttpRequest.prototype, 'responseText').and.returnValue(JSON.stringify({ error: true }));
+    // then
+    uAjax.get(url)
+      .then(() => done.fail('resolve callback called'))
+      .catch((message) => {
+        expect(message).toBe('');
+        done();
+      });
+  });
+
+  it('should make request and fail with HTTP error code', (done) => {
+    // when
+    const status = 401;
+    spyOnProperty(XMLHttpRequest.prototype, 'status').and.returnValue(status);
+    // then
+    uAjax.get(url)
+      .then(() => done.fail('resolve callback called'))
+      .catch((message) => {
+        expect(message).toBe(`HTTP error ${status}`);
+        done();
+      });
+  });
+
+  it('should make request and fail with JSON parse error', (done) => {
+    // when
+    spyOnProperty(XMLHttpRequest.prototype, 'status').and.returnValue(200);
+    spyOnProperty(XMLHttpRequest.prototype, 'responseText').and.returnValue(invalidResponse);
+    // then
+    uAjax.get(url)
+      .then(() => done.fail('resolve callback called'))
+      .catch((message) => {
+        expect(message).toContain('JSON');
+        done();
+      });
+  });
+
+});