<script type="text/javascript">
document.getElementById("frame1").height="300";
document.getElementById("frame1").width="300";
document.getElementById("frame1").height="200";
document.getElementById("frame1").width="200";
<iframe src="/example/hdom/frame_a.html" id="frame1" height="200" width="200"></iframe>
<input type="button" onclick="changeSize()" value="Change size" />
<input type="button" onclick="restoreSize()" value="Restore size" />