How to access variables in an iframe?(Opera,JavaScript)

[cx]

I want to acess a variable in the iframe, the following code runs well
in Firefox and IE, but fails in Opera. Can I modify the code to meet
opera's standard?

a.htm:
<iframe id=q src="b.htm"></iframe>
<script>
var i;
var l=document.getElementById('q');
alert(l.kkk);
</script>

b.htm:
<script>
var kkk=1;
</script>

 

[BootNic]

I want to acess a variable in the iframe, the following code runs well
in Firefox and IE, but fails in Opera. Can I modify the code to meet
opera's standard?

a.htm:
<iframe id=q src="b.htm"></iframe>
<script>
var i;
var l=document.getElementById('q');
alert(l.kkk);
</script>

b.htm:
<script>
var kkk=1;
</script>

<script type="text/javascript">
var l=document.getElementById('q');
l.onload=function(){alert(l.contentWindow.kkk)}
</script>