When to use window.opener / window.parent / window.top

Question

In JavaScript when to use window.opener / window.parent / window.top ?

Answer 1

I think you need to add some context to your question. However, basic information about these things can be found here:

window.opener https://developer.mozilla.org/en-US/docs/Web/API/Window.opener

I've used window.opener mostly when opening a new window that acted as a dialog which required user input, and needed to pass information back to the main window. However this is restricted by origin policy, so you need to ensure both the content from the dialog and the opener window are loaded from the same origin.

window.parent https://developer.mozilla.org/en-US/docs/Web/API/Window.parent

I've used this mostly when working with IFrames that need to communicate with the window object that contains them.

window.top https://developer.mozilla.org/en-US/docs/Web/API/Window.top

This is useful for ensuring you are interacting with the top level browser window. You can use it for preventing another site from iframing your website, among other things.

If you add some more detail to your question, I can supply other more relevant examples.

UPDATE: There are a few ways you can handle your situation.
You have the following structure:

• Main Window
  • Dialog 1
    • Dialog 2 Opened By Dialog 1

When Dialog 1 runs the code to open Dialog 2, after creating Dialog 2, have dialog 1 set a property on Dialog 2 that references the Dialog1 opener.

So if "childwindow" is you variable for the dialog 2 window object, and "window" is the variable for the Dialog 1 window object. After opening dialog 2, but before closing dialog 1 make an assignment similar to this:

childwindow.appMainWindow = window.opener

After making the assignment above, close dialog 1. Then from the code running inside dialog2, you should be able to use window.appMainWindow to reference the main window, window object.

Hope this helps.