The Input Mask server control is an input control that lets the user enter text inside a preset mask. By default, the MaskFormat property of the control is set to MaskType.PhoneNumber, which displays the phone number mask inside the text box. However, the Input Mask control can also display 7 other unique mask types. The text displayed in the Input Mask control is specified or determined by using the Text property. The Input Mask control contains all the members of the System.Web.UI.WebControls.Textbox server control. In addition, several other members have been added to facilitate the implementation of the mask capabilities.