How to prevent WebView from changing window position on the screen?

Question

Objective-C

The situation is as follows:
There is a window with a WebView, the Vkontakte authorization page is loaded into the WebView (display=popup).
The JavaScript of this page has a code that moves the popup to the middle of the screen:

window.moveTo(Math.floor((screen.width - 620) / 2), Math.floor((screen.height - box.offsetHeight - 190) / 2));

Because of this code, the application window will also move to the middle of the screen:

How to prevent WebView from changing the position of the window on the screen?