function CheckEmailAddress(EmailAddr:string):integer;
var TempLen,TempResult:integer;
begin
TempLen:=length(EmailAddr);
TempResult:=0;
if pos('@',EmailAddr)<=1 then TempResult:=TempResult+1;
if (pos('.',EmailAddr) =TempLen) or (pos('.',EmailAddr)=pos('@',EmailAddr)+1)
then TempResult:=TempResult+2;
result:=TempResult;
end;
//调用:
case CheckEmailAddress('@99.com') of
0: ;//正确格式
1: ;//@位置不正确
2: ;//.位置不正确
3: ;//@位置不正确,.位置也不正确
end;