JSFiddle - React, Tailwind, and code Playground

by Michel Plungjan

HTML

<ul>
  <li><a id="tree1_link" href="#">Sport</a>
    <ul id="tree1" style="display:none">
      <li><a href="national_sport.php">National Sport</a></li>
      <li><a href="international_sport.php">International Sport</a></li>
    </ul>
  </li>
</ul>

JavaScript

window.onload=function() {
  var links = document.getElementsByTagName("a");
  for (var i=0, n=links.length;i<n;i++) {
    if (links[i].id.indexOf("_link") !=-1) {
      links[i].onclick=function() {
        var id=this.id.split("_")[0]; // get the prefix
        var sub = document.getElementById(id);
        sub.style.display=sub.style.display=="block"?"none":"block";
        return false;
      }
    }
  }
}