It works in firefox, IE 6 but not opera.

please help me see what is wrong

Code:
 
<div style="width:100%">
   <div style="width:50%;float:left;">...</div>
   <div style="width:50%;float:right">...</div>
   <div style="clear:both"></div>
</div>
 
<div style="margin-top:20px">...</div>
In the above code, the bolded tags do not work in Opera. The div clearer doesn't seem to work.

Opera does not show the margin. How do i fix this?