<html>
<script>
function changeFrame()
{
document.getElementsByTagName('frame')[0].style.border = '10px solid blue';
}
window.addEventListener('DOMContentLoaded', changeFrame, false);
</script>
<frameset rows="50%,*" cols="*">
<frame src="target-frameset-frame.html" scrolling="auto">
</frameset>
</html>