If you've ever tried to close a browser window from ASP.NET by using the following code:
<input type="button" class="inputfields"
onclick="javascript:window.close();" value="Close" /></td>
You will probably receive the following message:
http://blogs.infinite-x.net/images/JavascriptHowtoClose.closeWithoutWarning_D055/image06.png
After digging around for 20 minutes or so, I finally found the answer on Anatoly Lubarsky's http://blogs.x2line.com/al/articles/350.aspx:
<input type="button" class="inputfields"
onclick="javascript:window.opener='x';window.close();" value="Close" /></td>