title: How to listen string change on url javascript
body: <p>I want to get the string (base64) from url, but it keeps changing at 30 seconds, the url only contains a string from a qr code, i want to be able to listen everytime this string changes, how can i do that using js?</p>
  <p><a href="https://i.stack.imgur.com/LgsgL.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LgsgL.jpg" alt="url body" /></a></p>
  <p>ps: the url don't change, just it content</p>