JavaScript 中,nodeValue节点值是什么东西?我怎么实验不出来?

<div id="AAAid" name="AAAname">1111</div>
<div id="BBBid" name="BBBname">2222</div>
<div id="CCCid" name="CCCname">3333</div>
<input type="button"  id="DDDid"  name="DDDname" value="delAll" ><br>
<input type="text" id="EEEid"  name="EEEname" value="asdf">

var AAA=document.getElementById('AAAid');
var DDD=document.getElementById('DDDid');   
var EEE=document.getElementById('EEEid');

console.log(AAA.nodeValue);
console.log(DDD.nodeValue);
console.log(EEE.nodeValue);