how to sync window.top.location and window.location?
This is how you set the parent of the frame (top) to the location of the frame document...
top.location = self.location;
Of course, this code must be executed within the iframe, and is succeptible to the Same-Origin Policy.
Anant Dabhi
window.top.location is return you to broswer's address bar location even you'r in i-frame or page.. window.location is return location of your current page address in case facebook apps. if you want to top query-string you have to use
alert(window.top.location);
if u want to replace top location then
window.top.location = "http://whatever.com";
来源：https://stackoverflow.com/questions/5354561/window-top-location-vs-window-location