function Is_Event_selected(sender, args) {

debugger;

var lstbox = $find("lstEvents");

var chkedItems_Count = lstbox.get_checkedItems().length;

args.IsValid = chkedItems_Count > 0;

}

<div>

<asp:CustomValidator ID="CV_lstEvents" runat="server" ValidateEmptyText="true" ClientValidationFunction="Is_Event_selected"

ControlToValidate="lstEvents" ErrorMessage="please Select Items(s)" ValidationGroup="Event_Group_Validation">

</asp:CustomValidator>

<telerik:RadListBox ID="lstEvents" runat="server" Width="100%" MaxHeight="225px"

CheckBoxes="true" AutoPostBack="false" EmptyMessage="Select Event" CausesValidation="false" >

<Items>

<telerik:RadListBoxItem Text="Ajax Controls" Value="0" />

<telerik:RadListBoxItem Text="BI Controls" Value="1" />

<telerik:RadListBoxItem Text="SilverLight" Value="2" />

<telerik:RadListBoxItem Text="KenDo UI" Value="3" />

</Items>

</telerik:RadListBox>

<asp:Button ID="btn" runat="server" ValidationGroup="Event_Group_Validation" />

</div>

Hi,
I am getting obj for radtreeview in javascript by using document.getElementById(...) but same thing is not getting by using $find(..).
If i get obj form the documnet class i am not able to get nodes form the tree obj... My code is looks like

<telerik:RadScriptBlock ID="rcb" runat="server">

 <script type="text/javascript">

 debugger;

Generate_WhereCondition1();

</script>

 if(tree==null)

tree=document.getElementById("<%= tvfltview.ClientID %>"); // here i am getting obj -- type 2

</telerik:RadScriptBlock>

but i can getting error for tree.get_nodes(); from type 2