Limit input in a textbox?

Question

Is there any way to limit the number of characters that can be placed in a textbox or similar input device, and hopefully also limit the input to either alphabetic or numeric symbols? For example, if I wanted to allow a player to input his or her own height and weight, but didn't want players screwing the game up by entering letters because those values are likely to change (and also didn't want any 15-foot tall, 2000-pound characters in the game)?

Answer 1

The answer to the Interactive Textbox Limitations question describes some of techniques you can use to achieve the result you want.