Confirm Box in Asp.Net

1, in the back-end us the attributes added

 imgReactivateList.Attributes.Add("onclick", "return confirmMsg('Do you wish to put this property back Online?');")

2, at the front-end use the client onclick

 <asp:Button ID="Delete_Profile" runat="server" CssClass="submitBtn"                         Text="Delete Profile" onclick="Delete_Profile_Click" OnClientClick = " return confirm('Are you sure to Delete your Profiles ?');"/>