Frames, like form elements and windows, have event handlers. A frame’s event handlers (onLoad, onUnload, onFocus and onBlur) can make your program wait until some critical event takes place in a frame ...
当前正在显示可能无法访问的结果。
隐藏无法访问的结果当前正在显示可能无法访问的结果。
隐藏无法访问的结果