I know we can use masked text box in windows form. However, this control is not available in visual web part. I would like to set up a input mask for a textbox as "99-99". Can anyone give me some help? Thanks

Not OOB, you can try using jquery and CEWP to achieve this. Refer to the following post for more information

http://pawansatope.blogspot.com/2012/02/input-mask-on-textbox-in-sharepoint.html

http://sharepoint711.wordpress.com/2012/11/14/masking-on-sharepoint-list-column/

Thanks. I used the method of the last reference.