DOM Window object still refers to window.top inside frame on iPhone

Trying to execute a such script in iPhone web browser gives you false:

var frameWindow = window.frames[0];
return new frameWindow['Functio开发者_Go百科n']('return (window.self != window.top).apply(null, arguments);');

This code returns FALSE on iPhone, but in Chrome and Safari it works correctly and returns TRUE (which is actually should be true).

Seems like the window object still referes to window.top even if the script was compiled for the frame window.

Anyone knows this issue?