Tryit Editor v2.7

Edit This Code:
<!DOCTYPE html>
<html>
<head>
<script>
  onerror = handleErr;
  var txt = "";
  function handleErr(msg, url, l) {
    txt = "There was an error on this page.\n\n";
    txt += "Error: " + msg + "\n";
    txt += "URL: " + url + "\n";
    txt += "Line: " + l + "\n\n";
    txt += "Click OK to continue.\n\n";
    alert(txt);
    return true;
  }

  function message() {
    adddlert("Welcome guest!");
  }
</script>


</head>

<body>
<input type="button" value="View message" onclick="message()">
</body>

</html>