description

# top property Null safety

WindowBase? top

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'

## Implementation

    WindowBase? get top;