Test Code 4:
[Ctrl+A Select all Note:Introducing external Js requires refreshing the page before execution]
Test results:
Firefox3："BODY"
Internet Explorer 7："BODY"
Opera 9.51："BODY"
Chrome 0.2："BODY"
Safari 3："BODY"
in conclusion:
When only a certain element has CSS positioning and its parent element and its DOM structure level have not CSS positioning, the value of the offsetParent property of this element is HTMLBODYElement. More specifically, the reference object for the various offset calculations of this element (offsetTop, offsetLeft, etc.) is the Body element.
OK, that's all for the offsetParent property.
As for what to write in the next article, I haven't figured it out yet.