By Opera Software

From Opera 15 onward, Opera 11 & 12’s extension format is no longer supported, and instead, we’ve switched to Chromium’s extension model. Check out our new documentation for developing extensions for Opera 15 and higher and start building your own extensions.


The readonly tabGroups attribute exposes a window tab group manager. The tab group manager is an object that implements the BrowserTabGroupManager interface and manages all browser tab groups that are currently open within the context window.


readonly BrowserTabGroupManager tabGroups


The following example creates a button in the browser toolbar. When the button is clicked, the last focused window is detected. The number of tab groups in the window is then displayed in the button's badge.

// The background process (e.g. index.html)

// Specify the properties of the button before creating it.
var UIItemProperties = {
  disabled: false,
  title: "Example extension",
  icon: "images/icon_18.png",
  badge: {
    backgroundColor: '#cc0000',
    color: '#ffffff'

// Create the button and add it to the toolbar.
var button = opera.contexts.toolbar.createItem( UIItemProperties );

button.addEventListener('click', handleClick, false);

function handleClick() {
  // Get the last focused window
  var win =;

  // Get all groups in the window
  var groups = win.tabGroups.getAll();

  // Display the number of groups in the button's badge
  button.badge.textContent = groups.length;

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