if语句不管是true还是false都能执行里面的代码，奇怪！
<%
dim aaa
aaa = Request.Form( "aaa ")
if Not IsNull(aaa) or Not IsEmpty(aaa) then
Request.Write( "aaa ")
end if
%>

这里总是打印“aaa”，不管if语句是否为真

[解决办法]
<%
dim aaa
aaa = Request.Form( "aaa ")
if aaa <> " " then
Request.Write( "aaa ")
end if
%>