Here's how to spell check a textbox in a Detailview:
| <script type="text/javascript"> | 
| function startSpell() { | 
| var sources = document.getElementById('<%=DetailsView1.FindControl("CommentTextBox").ClientID %>'); | 
| var spell = $find("<%=RadSpell1.ClientID%>"); | 
| spell.set_textSource(new Telerik.Web.UI.Spell.HtmlElementTextSource(sources)); | 
| spell.startSpellCheck(); | 
| } | 
| </script> | 
| <telerik:RadSpell ID="RadSpell1" Runat="server" ControlToCheck="DetailsView1" | 
| ButtonType="None" Height="28px" /> | 
| <input type="button" onclick="startSpell();" value="Check all"/> | 
