title: Validate Phone number textbox
body: <p>I want to know how I can validate a phone number in a textbox using this code: </p>
  
  <pre><code>System.Text.RegularExpressions.Regex rphone = new System.Text.RegularExpressions.Regex(@"^((\+){0,1}91(\s){0,1}(\-){0,1}(\s){0,1}){0,1}9[0-9](\s){0,1}(\-){0,1}(\s){0,1}[1-9]{1}[0-9]{7}$");
  </code></pre>