急！怎么给注册信息作个判断语句，最好是有源码（ASP）！谢谢

user=trim(request.form("user")) '用户名
pass=trim(request.form("pass")) ‘密码
pass2=trim(request.form("pass2")) ’密码
if instr(user,"&")>0 then
response.write "<font color=red><center>用户名称包含非法字符！</center></font>"
response.end
end if
if instr(pass,"&")>0 or instr(pass,"=")>0 then
response.write "<font color=red><center>密码包含非法字符！</center></font>"
response.end
end if
if instr(pass2,"&")>0 or instr(pass2,"=")>0 then
response.write "<font color=red><center>密码包含非法字符！</center></font>"
response.end
end if

if user="" or pass="" then
response.write "<font color=red><center>用户名称和密码不能为空</center></font>"
response.end
end if
if pass<>