Telerik RadMaskedTextBox is an enhanced data entry control which uses a mask to distinguish between proper and improper user input.
You can use a mask to specify the accepted format such as IP address, telephone number, currency, etc. It shares the common properties of all RadInput controls,
including support for skins, styles for different states, conditional postback on text change, flexible caret and button positioning, labels, and so on.
About RadMaskedTextBox for ASP.NET AJAX
When you need versatile data entry controls that restricts the users input, Telerik
MaskedTextBox control for ASP.NET AJAX is the perfect match. You can use a mask to specify the accepted format such as IP address, telephone number, currency, and so on. In addition,
you can use RadMaskedTextBox together with validators such as the RequiredValidator and RegularExpressionValidator controls to enforce any custom validation logic
RadMaskedTextBox and 90+ other controls are part of UI for ASP.NET AJAX, a comprehensive toolset taking
care of the common functionality of your application, while leaving you with more
time to work on its business logic.