unmanaged code, 279
upgrading to ASP.NET. See moving to ASP.NET
uploading files, 46–47
URL authorization, 216–218
User controls
caching, 31, 164–167, 284
CurrentTime.ascx, 30
FavoriteColor.ascx, 31
IncludeCurrentTime.aspx, 30
partial page caching of, 164–167
property setters in, 31–32
purpose of, 30
updating performance hit, 284
user interfaces, mobile, 91
user names, storing, 211
User-Agent headers
caching, 147–148
mobile browser configuration with, 99–102