A reference to the topmost window in the window hierarchy.
If this WindowBase is the topmost WindowBase, top will return a reference to the WindowBase itself.
// Add an IFrame to the current window.
IFrameElement myIFrame = new IFrameElement();
window.document.body.elements.add(myIFrame);
// Add an IFrame inside of the other IFrame.
IFrameElement innerIFrame = new IFrameElement();
myIFrame.elements.add(innerIFrame);
print(myIframe.contentWindow.top == window) // 'true'
print(innerIFrame.contentWindow.top == window) // 'true'
print(window.top == window) // 'true'
Source
WindowBase get top;