title: How to accept more than 1 HTML5 pattern on an input?
body: <p>I'm working on a form where I have to get book's ISB numbers. ISBN numbers can be 9 or 13 digits long and i would like to check the input with HTML5 pattern, but I've to accept 9 or 13  long numbers both.</p>
  
  <p>How can I write it down with HTML5?</p>