title: Regular expression for GB based and only numeric phone number
body: <p>I want a regular expression code which allows only numeric phone number (e.g 1234567890) as well as GB format number (e.g 123-456-7890).</p>
  
  <p>This expression must have to work for both conditions.</p>
  
  <p>Currently I am using below regular expression which only allows GB phone number</p>
  
  <pre><code>/^(\()?\d{3}(\))?(-|\s)?\d{3}(-|\s)\d{4}$/ 
  </code></pre>
  
  <p>I need help to allow only numeric number also.</p>