diff --git a/js/src/dialog.js b/js/src/dialog.js
new file mode 100644
index 0000000..d8334cb
--- /dev/null
+++ b/js/src/dialog.js
@@ -0,0 +1,86 @@
+/*
+ * 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 { lang as $ } from './initializer.js';
+
+export default class uDialog {
+
+  /**
+   * Builds modal dialog
+   * @param {(string|Node|NodeList|Array.<Node>)} content
+   */
+  constructor(content) {
+    const dialog = document.createElement('div');
+    dialog.setAttribute('id', 'modal');
+    const dialogHeader = document.createElement('div');
+    dialogHeader.setAttribute('id', 'modal-header');
+    const buttonClose = document.createElement('button');
+    buttonClose.setAttribute('id', 'modal-close');
+    buttonClose.setAttribute('type', 'button');
+    buttonClose.setAttribute('class', 'button-reject');
+    buttonClose.setAttribute('data-bind', 'onCancel');
+    const img = document.createElement('img');
+    img.setAttribute('src', 'images/close.svg');
+    img.setAttribute('alt', $._('close'));
+    buttonClose.append(img);
+    dialogHeader.append(buttonClose);
+    dialog.append(dialogHeader);
+    const dialogBody = document.createElement('div');
+    dialogBody.setAttribute('id', 'modal-body');
+    if (typeof content === 'string') {
+      dialogBody.innerHTML = content;
+    } else if (content instanceof NodeList || content instanceof Array) {
+      for (const node of content) {
+        dialogBody.append(node);
+      }
+    } else {
+      dialogBody.append(content);
+    }
+    dialog.append(dialogBody);
+    this.element = dialog;
+    this.visible = false;
+  }
+
+  /**
+   * Show modal dialog
+   */
+  show() {
+    if (!this.visible) {
+      document.body.append(this.element);
+      this.visible = true;
+    }
+  }
+
+  /**
+   * Remove modal dialog
+   */
+  destroy() {
+    document.body.removeChild(this.element);
+    this.visible = false
+  }
+
+  /**
+   * Show confirmation dialog and return user decision
+   * @param {string} message
+   * @return {boolean} True if confirmed, false otherwise
+   */
+  static isConfirmed(message) {
+    return confirm(message);
+  }
+}
diff --git a/js/test/dialog.test.js b/js/test/dialog.test.js
new file mode 100644
index 0000000..a0741b7
--- /dev/null
+++ b/js/test/dialog.test.js
@@ -0,0 +1,116 @@
+/*
+ * 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 { config, lang } from '../src/initializer.js';
+import uDialog from '../src/dialog.js';
+import uObserve from '../src/observe.js';
+
+describe('Dialog tests', () => {
+
+  let content;
+  let dialog;
+
+  beforeEach(() => {
+    config.reinitialize();
+    lang.init(config);
+    spyOn(lang, '_').and.returnValue('{placeholder}');
+    content = 'Test content';
+    dialog = new uDialog(content);
+  });
+
+  afterEach(() => {
+    document.body.innerHTML = '';
+    uObserve.unobserveAll(lang);
+  });
+
+  it('should create dialog with string content', () => {
+    // when
+    const body = dialog.element.querySelector('#modal-body');
+    // then
+    expect(body.innerHTML).toBe(content);
+    expect(dialog.visible).toBe(false);
+  });
+
+  it('should create dialog with node content', () => {
+    // given
+    content = document.createElement('div');
+    dialog = new uDialog(content);
+    // when
+    const body = dialog.element.querySelector('#modal-body');
+    // then
+    expect(body.firstChild).toBe(content);
+  });
+
+  it('should create dialog with node array content', () => {
+    // given
+    content = [
+      document.createElement('div'),
+      document.createElement('div')
+    ];
+    dialog = new uDialog(content);
+    // when
+    const body = dialog.element.querySelector('#modal-body');
+    // then
+    expect(body.children[0]).toBe(content[0]);
+    expect(body.children[1]).toBe(content[1]);
+  });
+
+  it('should create dialog with node list content', () => {
+    // given
+    const div1 = document.createElement('div');
+    const div2 = document.createElement('div');
+    const el = document.createElement('div');
+    el.append(div1, div2);
+    content = el.childNodes;
+    dialog = new uDialog(content);
+    // when
+    const body = dialog.element.querySelector('#modal-body');
+    // then
+    expect(body.childNodes).toEqual(content);
+  });
+
+  it('should show dialog', () => {
+    // when
+    dialog.show();
+    // then
+    expect(document.querySelector('#modal')).toBe(dialog.element);
+    expect(dialog.visible).toBe(true);
+  });
+
+  it('should destroy dialog', () => {
+    // given
+    dialog.show();
+    // when
+    dialog.destroy();
+    // then
+    expect(document.querySelector('#modal')).toBe(null);
+    expect(dialog.visible).toBe(false);
+  });
+
+  it('should show confirm dialog', () => {
+    // given
+    const message = 'confirm message';
+    spyOn(window, 'confirm');
+    // when
+    uDialog.isConfirmed(message);
+    // then
+    expect(window.confirm).toHaveBeenCalledWith(message);
+  });
+
+});