Load Google Ads at the end

[agriz]

<script type="text/javascript">
window.onload = function() {
	document.getElementById('google_right_ad').appendChild(document.getElementById('ad1_footer'));
	document.getElementById('ad1_footer').style.display = '';
}
</script>

I used this code. This is working only in firefox. It is not working chrome and internet explorer.

ad1_footer has the google adsense code at the bottom of the page.
I am moving that ad to google_right_ad id once the page is loaded.

But it is not working on two major browsers.