Is there an event handler that fire event when the desired button is available in ComObj?

[my-lord]

Hello guys.I want to perform some action when the element, which has the desired class, loaded.There is a page that will load after some file processing and when the page finished the process then the button is available and I want to click the button.Is there an event handler to listen to this event?

For example,
When button that has "huge track" class is available then perform following action:
w.document.getElementsByClassName("button huge track")[0].Click()