>When the user puts in just digits, I know it's numeric. If he puts in just characters, I know it's a string. But how do I know that when the user puts in '123 piano' that it is character if the type() function returns 'U' and the val() function return 123.00 (sugesting it is numeric). What I do now is I test each character separately, but I want to know if there is no other, easier way.

As you said, it's always character string but if type() function returns "N" it represents numeric expression that can be converted with VAL() function to a number. IOW, type(textbox.value)) evaluates textbox.value and tells you what the type of evaluation is. The textbox.value still a character. The "U" returned means that VFP cannot convert textbox.value to any known type.