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This documentation relates to Opera's now deprecated .oex Extension API framework for Opera versions <= 12.15 and also provided by our OEX2NEX shim library.

For the latest Opera Extensions API documentation for Opera versions > 12.15 please consult the latest Opera Extensions API documentation online.


The readonly browserWindow attribute exposes the context window. On getting, the browserWindow attribute returns a BrowserWindow object representing the context window.

This attribute is named browserWindow and not window to avoid confusion with the global window object.


readonly BrowserWindow browserWindow


The following example creates a button on the browser toolbar. When the button is clicked, the first tab group's parent window is detected. If the window is not private, a new private window is opened with the URLs of the first tab group.

// 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",
  onclick: function() {
    try {
      // Get the first tab group
      var group = opera.extension.tabGroups.getAll()[0];
      // Get all tabs within the tab group
      var tabs = group.tabs.getAll();
      // Create an empty array and add the URL of each tab to it
      var newTabs = [];      
      for (var i = 0, len = tabs.length; i < len; i++) {
        if (tabs[i].url != undefined) {
          newTabs.push({url: tabs[i].url});
      // Get the tab groups's browser window
      var win = group.browserWindow;
      // If the window is not private, open a new private window with the tab group's URLs
      if (win.private === false) {
        opera.extension.windows.create(newTabs, {private: true});
    } catch(e) {}

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