Javascript edit iframe when content of textarea

[moschino]

\[code\]<script type="text/javascript">function change() {document.getElementById('target').getElementsByTagName('html').getElementsByTagName('body').innerHTML = document.getElementById('src').value;}</script><textarea id="src" onchange="change();"></textarea><br/><iframe id="target"></iframe>\[/code\]This is my code and I don't understand why it isn't working. No jQuery please. I know things like this exist for example htmledit squarefree I have tried frame instead of iframe and that hasn't worked either