代码:
运行以上代码，IE里提示：未知的运行错误。FF测试是正确的。
Goole一下，innerHTML 对下面的对象只读（<=IE7）：table,thead,tfoot,tbody,tr,col,colgroup,html,title,style,frameset等。
上面所说的innerHTML属性只读的对象中并不包括p，为什么还报错。
再google，找到这么一段：
The<p>tag can be nested within certain tags and certain tags can be nested within it. The general rule is that the paragraph has to be its own block. Therefore, a paragraph tag cannot be nested within a tag expecting only text or inline elements, nor can another block element tag be nested within a paragraph tag.
For instance, you cannot nest paragraph tags and heading tags.
You can also put paragraph tags within division tags but not the other way around.
A paragraph tag can be placed within a table cell or other tags structures that are not text only. It can also be placed within a list item. This means you can have long, multi-paragraph list items. Anything can be nested within a<p>tag that is allowed within the flow of the text. All style tags are allowed within a paragraph since they format text. Links and images can be placed within paragraphs, and the<br />tag exists for the exclusive purpose of breaking the line without ending the paragraph.
If a Web browser encounters a tag within a paragraph that cannot be nested within paragraph tags, it will assume that the paragraph has ended.
大家自己看吧， 其中的大意之一：p标签不能包容div、h1除了<br />等块级元素。
所以IE报未知的运行错误原因就是innerHTML里有div标签，另外往p元素里插入div元素也会失败 【p.appendChild（div）】
最后，蓝色理想上的一篇blank的“innerHTML的一些问题”。