如何判断字符串是否是有效EMAIL地址

function IsEMail(EMail: String): Boolean;
var s: String;ETpos: Integer;
begin
ETpos:= pos(''@'', EMail);
if ETpos > 1 then
begin
s:= copy(EMail,ETpos+1,Length(EMail));
if (pos(''.'', s) > 1) and (pos(''.'', s) < length(s)) then
Result:= true else Result:= false;
end
else
Result:= false;
end;