IFRAMEs, .contentWindow, .contentDocument区别

from: http://www.omnigroup.com/mailman/archive/omniweb-l/2003/015196.html



> I'm working on a web site that uses inline frames (iframes), with the 


> following code to interact with javascripts in the frame:


>


> panelFrame=document.getElementById('panelFrame');


> panelFrame.contentWindow.somefunction();


>


> Now, OmniWeb and Safari both fail on this while Mozilla and IE both 


> work. I did some checking, and it turns out that IFRAME.contentWindow 


> is not part of the DOM2 spec. Both OmniWeb and Safari support the 


> DOM-standard .contentDocument property, which refers to the document 


> object of that frame. Javascript global variables and functions, 


> however, are stored on the window object, not the document object, 


> hence the .contentWindow property that's supported by Mozilla and IE.