/**
 Initializes main menu of Vintasoft web document viewer.
 @param {object} docViewerSettings Settings of Vintasoft web document viewer.
*/
function __initMenu(docViewerSettings) {
    // get items of document viewer
    var items = docViewerSettings.get_Items();

    // get the main menu of document viewer
    var mainMenu = items.getItemByRegisteredId("mainMenu");
    // if main menu is found
    if (mainMenu != null) {
        // get items of main menu
        var mainMenuItems = mainMenu.get_Items();

        // get "Tools" menu in web document viewer
        var toolsToolbarPanel = mainMenuItems.getItemByRegisteredId("toolsMenuPanel");
        // get items of "Tools" menu
        var toolsToolbarPanelItems = toolsToolbarPanel.get_Items();

        // create the first button
        var button1 = new Vintasoft.Imaging.UI.UIElements.WebUiButtonJS({
            cssClass: "vsui-button vsdv-sidePanel-textSearchPanelButton",
            title: "Button1",
            localizationId: "button1",
            onClick: function (event, uiElement) {
                alert('Button1 is clicked.');
            }
        });

        // create the second button
        var button2 = new Vintasoft.Imaging.UI.UIElements.WebUiButtonJS({
            cssClass: "vsui-button vsdv-sidePanel-textSelectionPanelButton",
            title: "Button2",
            localizationId: "button2",
            onClick: function (event, uiElement) {
                alert('Button2 is clicked.');
            }
        });

        // create the toggle button
        var toggleButton1 = new Vintasoft.Imaging.UI.UIElements.WebUiToggleButtonJS(
            { raiseClickEventWhenTogglePanelOpening: false },
            [button1, button2],
            { cssClass: "vsui-togglePanel" });

        // add the toggle button to the "Tools" menu in web document viewer
        toolsToolbarPanelItems.addItem(toggleButton1);
    }
}