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 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 current tab's parent window is detected. If the window is not private, a new private window is opened with the URL of the current tab.

// 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() {
    // Get the currently selected tab
    var thisTab = opera.extension.tabs.getSelected();

    // Get the tab's browser window
    var thisWin = thisTab.browserWindow;

    // If the window is not private, open a new private window with the tab's URL
    if (thisWin.private === false) {[{url: thisTab.url}], {private: true});


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

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