<com:TContent ID="Content"> <style type="text/css"> .errorclassA, .errorclassB { background-color:pink; } </style> <com:TTextBox ID="A" /> <com:TRequiredFieldValidator ControlToValidate="A" Text="Required!" ControlCssClass="errorclassA" ValidationGroup="A"/> <com:TEmailAddressValidator ControlToValidate="A" Text="No Email!" ControlCssClass="errorclassA" ValidationGroup="A"/> <com:TButton Text="Click" ValidationGroup="A" /> <br /> <com:TTextBox ID="B" /> <com:TRequiredFieldValidator ControlToValidate="B" Text="Required!" ControlCssClass="errorclassB" ValidationGroup="B" EnableClientScript="False" /> <com:TEmailAddressValidator ControlToValidate="B" Text="No Email!" ControlCssClass="errorclassB" ValidationGroup="B" EnableClientScript="False" /> <com:TButton Text="Click" ValidationGroup="B" /> </com:TContent>