[jQuery] Iframe onload safari

Hello,
I'm trying to output an alert box on load of an iframe. Here is the
code I am using:
<script type="text/javascript">
$(document).ready(function() {
    $(window.frames[0]).load(function() {
        alert('done loading');
    });
});
</script>
It works in Firefox, but not in Safari. Any ideas as to why?
Thank you,
Wesley