Using RegularExpressionValidator to display asterisk on the next label

Question

I have a request that I'm having difficulty working out… Once the 'Name' field is completed, the 5 labels below it should show a red asterisk

Form

I've added a RegularExpressionValidator which dynamically displays a red asterisk next the name label once the textbox is populated and tabbed, however this isn't what's required.

RegularExpressionValidator

<asp:RegularExpressionValidator runat="server" ControlToValidate="txtNewDos" Display="Dynamic" CssClass=" mandatory" ValidationExpression="^([\S\s]{0,1})$"></asp:RegularExpressionValidator>

ASP

<asp:Label runat="server" ID="lblNumCurStudentsDos" Text="Number of Current PGR students supervised"></asp:Label>

CSS

 .mandatory:after { content:' *'; color:red } 

Can anybody point me in the right direction as to how I can populate my CSS class next the 5 labels once the Name text box has been populated?

Answer 1

Placing the RegularExpressionValidator within each label <td> </td> works

<asp:RegularExpressionValidator runat="server" ControlToValidate="txtNewDos"
  Display="Dynamic" CssClass=" mandatory" ValidationExpression="^([\S\s]{0,1})$">
</asp:RegularExpressionValidator>