//You will need to include KeyboardFilterCommonCode on your page for this to work.
 //<!--
function ClientNameFilter (event)
    {   
        try
        {
            var rv ; 
            var keyAscii = GetKeyAscii (event) ;
            
            if (IsCommonAscii(keyAscii) ) 
                {rv= true;}
            else    
                {  
            
                switch (true)
                    {   case (keyAscii==190 || keyAscii==32 || keyAscii==192 || keyAscii==189 || keyAscii==189):
                                // apostrophe, space, full stop ,hyphen and hyphen on numberpad
                            rv=true ;
                        break;
                        
                        case (keyAscii >64 && keyAscii<91):
                            //Letters of the alphabet
                            rv=true ;
                        break;   
                            
                        default:
                           //{alert(keyAscii);}
                            rv=false ;
                    }
                }
            return rv;
        }
        catch (ex)
            { }
    }
//-->