YouaredevelopinganASP.NETWebpagethatusesjQueryvalidation.TheusershouldenteravalidemailaddressinatextboxthathasIDtxtEmail.Thepagemustdisplay"E-Mailaddressrequired"whentheuserdoesnotenteranaddressand"Invalide-mailaddress"whentheuserentersanaddressthatisnotformattedproperly.Youneedtoensurethattheappropriateerrormessageisdisplayedwhenthetextboxdoesnotcontainavalide-mailaddress.Whichtwocodesegmentsshouldyouadd？（）
A.
B.
C.
D.
正确答案：参考B, D
