Office.initialize event (apps for Office)

The reason parameter of the initialize event listener function returns an InitializationReason enumeration value that specifies how initialization occurred. A task pane or content app can be initialized in two ways:

• The user just inserted it from Recently Used Apps section of the App drop-down list on the Insert tab of the ribbon in the Office host application, or from Insert app dialog box.

• The user opened a document that already contains the app.

Note
The reason parameter of the initialize event listener function only returns an InitializationReason enumeration value for task pane and content apps. It does not return a value for mail apps.

You can use the value of the InitializationEnumeration to implement different logic for when the app is first inserted versus when it is already part of the document. The following example shows some simple logic that uses the value of the reason parameter to display how the task pane or content app was initialized.

Office.initialize = function (reason) {
    // Checks for the DOM to load using the jQuery ready function.
    $(document).ready(function () {
    // After the DOM is loaded, app-specific code can run.
    // Display initialization reason.
    if (reason == "inserted")
    write("The app was just inserted.");

    if (reason == "documentOpened")
    write("The app is already part of the document.");
    });
}

// Function that writes to a div with id='message' on the page.
function write(message){
    document.getElementById('message').innerText += message; 
}