Masked Textbox Control

Does anyone know where I can find a tutorial to build a masked textbox or a pre-built component?

Thanks,

JSCheck out my free MTB control: http://www.eworldui.net
Along with Matt's control, you can find a variety of controls in this site's Control Gallery, www.123aspx.com, and www.411asp.net. My product,Professional Validation And More, includes 4 textboxes that filter keystrokes and more.

Masked textboxes use Javascript and depend on the good graces of the browser to determine just how much they work like Windows app masked textboxes. IE is the most powerful browser in this area. If you can limit yourself to IE-only users, then you may get the best UI. My own product has chosen a different route that works with more browsers: filter keystrokes and after the user exits the field, validate for errors and reformat if needed.