title: Change Variable after and at a certain amount of time
body: <p>I want to have a PDF document displayed in my app. This PDF document is a schedule and there is a link for every day from Monday to Friday (5 links in total). That means I need to change the download link for the PDF document reader every day at, say 5pm. </p>
  
  <p>My idea is to create a variable, this variable contains 5 strings, and every day the string is being changed to the next one in the list. When the list is finished, we start with the first link again.</p>
  
  <p>How do I do this?</p>