title: Lazy loading JSTREE
body: <p>I created a diagram of a tree in jstree.
  Because I have a lot of nodes data I want the load to be lazy.
  How is it possible that with every click on a parent there will be a call to mysql database and the children's will be retrieved?</p>
  <p>Like this idea:
  <a href="https://stackoverflow.com/questions/926781/how-to-only-display-a-treeview-expand-sign-if-children-exist/67149746#67149746">How to only display a TreeView expand sign [+] if children exist</a></p>
  <p>Thank you!</p>