关于DOM的nodeType

*元素-1
    <h1 id="h1">An HTML Document</h1>
    var element=document.getElementById("h1")
    element.nodeType = 1
    element.nodeName = H1
    element.nodeValue = null
*文本-3
    var element = document.getElementById("h1")
    var text = element.firstChild
    text.nodeType = 3
    text.nodeName = #text
    text.nodeValue = An HTML Document
*文档-9
    document.nodeType = 9
    document.nodeName = #document
    document.nodeValue = null   
*属性-2
    <input type="button" title="myTitle" id="myId" value="提交"/>
    var button = document.getElementById("myId")
    var attributes = button.attributes
    var second = attributes[1]
    second.nodeType = 2
    second.nodeName = title
    second.nodeValue = myTitle