window.open, waiting for document loading

[Yury Lobanov]

I have a C++ XPCOM

I need to open another window. I use

ret = mainWindow->Open(nsString(L"chrome://myapp/content/test_win.xul"), nsString(L"wname"), nsString(L"chrome,centerscreen,resizable=true"), &w);

then I need to wait until the page is loaded.
Other way the program crashes after

w->GetDocument(&d);

In Javascript I can use onload="calllback_func" in window tag.
How to do it in C++?
Searching all day in MDN and google have not helped.

[Yury Lobanov]

The problem solved by adding event listener to window object.