<!doctype html>
<div style="float:right;width:300px;margin:10px;height:100px;background-color:green"></div>

<table style="background-color:orange;margin-left:auto; margin-right:auto"><tr><td>This is a test and is demonstrating that auto width really 
should kick in here.</table>


<div style="overflow:hidden; max-width:300px; background-color:orange;margin-left:auto; margin-right:auto">This is a test and is demonstrating that auto width really 
should kick in here.</div>