javascript Error: There is already have event type code example

Example: global catch in javascript

<script>
  window.onerror = function(message, url, line, col, error) {
    alert(`${message}\n At ${line}:${col} of ${url}`);
  };

  function readData() {
    badFunc(); // Whoops, something went wrong!
  }

  readData();
</script>