title: How to make HTML input tag only accept numerical values?
body: <p>I need to make sure that a certain <code>&lt;input&gt;</code> field only takes numbers as value.
  The input is not part of a form. Hence it doesn't get submitted, so validating during submission is not an option. I want the user to be unable to type in any characters other than numbers.</p>
  
  <p>Is there a neat way to achieve this?</p>