如何使用JavaScript来警告这些PHP错误消息？

Question

How can I javascript alert my php error messages? Here is my code:

<?php echo showmessage($msg)?>

I want to make it into an alert, how can I do that?

Answer 1

 ?>
  <script type="text/javascript">
    alert("The error is  <?php echo $msg ?>");
    history.back();
  </script>
<?php

Or

echo '<script language="javascript">';
echo 'alert(Message here)';
echo '</script>';

Answer 2

The use of json_encode makes sure that characters that needs to be escaped are escaped.

<script>
  alert(<?php echo json_encode($msg); ?>);
</script>