Compare Validator and date format

[Mike P]

What date format does the Compare Validator check against? The date
format of the web server or of the client?

<asp:CompareValidator ID="CompareValidator2" runat="server"
Display="None"
ErrorMessage="Please enter a valid date in format dd/mm/yyyy"

ControlToValidate="txtDueDate" Type="Date"
Operator="DataTypeCheck"></asp:CompareValidator>