在MSDN中找到了
outHTML:
The property is read/write for all objects except the following, for which it is read-only: CAPTION, COL, COLGROUP, FRAMESET, HTML, TBODY, TD, TFOOT, TH, THEAD, TR. The property has no default value.
但是我的电脑上的 HTMLREF.CHM 中是这样写的:
The outerHTML property is read-only on the HTML, HEAD, BODY, FRAMESET, TBODY, TD, TFOOT, TH, THEAD, and TR objects.