I can't think of
$('#tb').textbox('textbox').bind('keydown', function(e){
if (e.keyCode == 13){ // when press ENTER key, accept the inputed value.
$('#tb').textbox('setValue', $(this).val());
$('#bSubmit').focus();
}else if(!(/[a-z ]/.test(e.key))) {
???????
}
});