function onClientItemsRequestedHandler(sender, eventArgs)  
{  
    if (sender.get_items().get_count() == 0)  
    {  
        sender.hideDropDown();          
    }  
}  
 
function onClientItemsRequestingHandler(sender, eventArgs)  
{      
   eventArgs.set_cancel(isLastCharNumber(eventArgs.get_text()));  
}  
 
function isLastCharNumber(str)  
{  
    var numbers = "1234567890";  
    if (str.length > 0)  
    {  
        var lastChar = str.substring(str.length - 1);  
        if (numbers.indexOf(lastChar) > -1)  
        {  
            return true;  
        }  
    }  
    return false;  
}  
 
function onClientDropDownOpeningHandler(sender, eventArgs)  
{  
    eventArgs.set_cancel(isLastCharNumber(sender.get_text()));  
}