ownerDocument 예제
<h1 id="hz">홈짱닷컴 Homzzang.com</h1>
<button onclick="homzzang()">클릭</button>
<p id="demo"></p>
<script>
function homzzang() {
var x= document.getElementById("hz").ownerDocument.nodeType;
document.getElementById("demo").innerHTML = x;
}
</script>
결과값: 9
※ ownerDocument : [object HTMLDocument]