I think you are following the codes given in article DateTimePicker in ASP.Net GridView using jQuery DateTimePicker Plugin
I downloaded the code and tested. It is working fine.
I can see one difference in your code.
The code should be like below...
<asp:TemplateField HeaderText="Date Of Birth">
<asp:TextBox ID="txtDOB" runat="server" ReadOnly="true" class = "Calender" />
<img src="calender.png" />
whereas you don't have the
Place your textbox for calendar and calendar image inside the
And one more thing. Make sure you have all css and js files added to the project.
In case you don't have them at correct path, this will not work.
You can see these errors in the console panel of the firebug of Mozilla browser.