title: Regex to allow only 1-31 numbers and disable letters & symbols
body: <p>I am using this regex for DayDate input=type[text]</p>
  <pre><code>^(0?[1-9]|[1@2][0-9]|3[01])$
  </code></pre>
  <p>I want to disable the option to enter letters which in my case users can.</p>
  <p>I cant use input=type[number]</p>
  <p>I found that <code>\D</code> is to allow only digits in the regex, but not sure where to place it in mine regex mentioned above</p>