title: what if i do not set error message in required field validator?
body: <p>If i do not set error message in required field validator, will it display msg pop up box or not? my code-</p>
  
  <pre><code>&lt;asp:RequiredFieldValidator runat="server" SetFocusOnError="true" 
    ValidationGroup="Search" ID="RFV_ddlTimeSlot" Display="None" 
    ControlToValidate="ddlTimeSlot" InitialValue="--Select Time Slot--"
    ErrorMessage=""&gt;&lt;/asp:RequiredFieldValidator&gt;
  </code></pre>