Prevent user from typing particular characters example does not work

[Emran]

I'm trying to disallow the up and down arrow key press on the text area of the combo (to ensure users do not accidentally select a different item) and used the following example provided in:
http://www.telerik.com/help/aspnet-ajax/combo-prevent-typing-particular-characters.html.

i am using firebug to step through the problem, the event fires however, the keypress is not disallowed.
I reverted back to example and noticed the example does not work too.

Please advise or post a working example.

<script type="text/javascript">
 function pageLoad() {
        var combo = $find("<%= RadComboBox1.ClientID %>");
        var input = combo.get_inputDomElement();
        input.onkeydown = onKeyDownHandler;
    }

    function onKeyDownHandler(e) {
        if (!e)
            e = window.event;

        var code = e.keyCode;
        //do not allow any of these chars to be entered: !@#$%^&*()
        //if (e.shiftKey && code >= 48 && code  <= 57){
        if (code >= 39 && code <= 40) {
            e.returnValue = false;
            if (e.preventDefault) {
                e.preventDefault();
            }
        }
    }
</script>  

<telerik:RadComboBox runat="server" ID="RadComboBox1" Height="400px"
            Width="100%" AllowCustomText="True"
            ShowMoreResultsBox="True"
            EnableVirtualScrolling="True"
            EnableLoadOnDemand="True"
            HighlightTemplatedItems="true"
            EnableItemCaching ="true"
            onitemsrequested="RadComboBox1_ItemsRequested"  
            onclientselectedindexchanged= "AllowSelectionChanged"
            onclientselectedindexchanging = "AllowSelectionChange"
            OnClientItemsRequesting="OnClientItemsRequesting"
            OnClientTextChange = "ValidateChange" Font-Size="X-Small"
  ShowDropDownOnTextboxClick="False">

[Princy]

Hi Emran,

Try the following JavaScript and check whether its working fine.

JavaScript:

function onKeyDownHandler(e)
{
   if (!e)
       e = window.event;
   var code = e.keyCode;
   //do not allow any of these chars to be entered: !@#$%^&*()
    if (code == 38 || code == 40)
    {
       e.cancel =true;
       try
       {
            e.returnValue = false;
            e.cancelBubble = true;
            if(document.all){ //IE
                e.keyCode = 0;
            }
            else{ //NS
                e.preventDefault();
                e.stopPropagation();
            }
        }catch(ex)
        {
        }
    }
}

Thanks,
Princy.

[Roman]

Hello,
The example provided here: http://www.telerik.com/help/aspnet-ajax/combo-prevent-typing-particular-characters.html, works on a qwerty keyboard; how about French-input keyboards (azerty)?
Is there a way to allow both input types?
Thanks