title: How to pre-define the text box for e-mail and/or phone number
body: <p>I am wondering if I have two text boxes for <strong>Phone</strong> and <strong>Mail</strong> how can I allow only digits (let's say US standard 1-234-567-8910) and only a real e-mail(aaaaaaa*<em>@<strong>bbb</strong>.</em>*cc) to my text boxes correspondingly in c#?   </p>