JavaScript中访问节点对象的方法有哪些？

复制代码 代码如下:

var obj = document.getElementById('fdafda');

var obj = document.f1;

obj.method="post";

obj.action='Bb';

var obj = document.f1.userName;

var obj = document.forms[0].userName;

var obj = document.forms[0].elements[0];

var obj = document.f1.elements[0];

var obj = document.forms["f1"].elements["userName"];

var obj = document.forms[0].like;

for(var i=0;i<obj.length;i++)

{

var aa = obj[i];

if(aa.checked)

{

alert();

}

}

<form name="f1" action="AA">

<input type="text" name="userName" id="userName"/>

<input type="checkbox" name="like" value="sport"/>

<input type="checkbox" name="like" value="art"/>

<input type="checkbox" name="like" value="music"/>

</form>

<form name="f1" action="AA">

<input type="text" name="userName" id="userName"/>

<input type="checkbox" name="like" value="sport"/>

<input type="checkbox" name="like" value="art"/>

<input type="checkbox" name="like" value="music"/>

</form>

<form name="f1" action="AA">

<input type="text" name="userName" id="userName"/>

<input type="checkbox" name="like" value="sport"/>

<input type="checkbox" name="like" value="art"/>

<input type="checkbox" name="like" value="music"/>

</form>