JSFiddle - React, Tailwind, and code Playground

by Paulpro

HTML

<a href="mailto: [email protected]">Mail</a>
<script>
  (function(w, d){
    var anchors = d.getElementsByTagName('a');
    var a = anchors[anchors.length - 1];

    a.onclick = function(){
      var old_unload = w.onbeforeunload;
      w.onbeforeunload = null;

      w.location = a.href;

      setTimeout(function(){
        w.onbeforeunload = old_unload;
      }, 0);

      return false;
    };

  })(window, document);
</script>

JavaScript

window.onbeforeunload = function(){
    return "Don't leave meeeeee!";
}