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ToX82/javascript-logger.php

Created May 3, 2020 11:03
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A simple script that captures the browser's JavaScript errors and send them to a server
Raw
javascript-logger.php
<?php
// Pt. 1) This is the server side part. We read the error (see pt. 2) and write it down using error_log
if (!empty($_POST)) {
$errorData = $_POST;
$error = " Error: " . $errorData['url'];
if ($errorData['error'] !== '') {
$error .= "<br><br>" . $errorData['error'];
}
if ($errorData['msg'] !== '') {
$error .= "<br><br>" . $errorData['msg'];
}
$error .= "<br><br>Browser info: " . $_SERVER['HTTP_USER_AGENT'];
error_log($error);
echo "Error detected!<br>";
echo $error;
}
?>
<?php
// Pt. 2) The following is the client side part.
// It is triggered by the window.onerror function, and makes an ajax request to the server side part.
?>
<html>
<head>
<title>Javascript Error Logger</title>
</head>
<body>
Hi! I am a simple button that creates Javascript errors!!
<button onclick="undefinedFunction('Something broke!');">Click me!</button>
<script>
// Tracking the error and sending it as an AJAX request to a php logger
window.onerror = function(msg, url, line, col, error) {
var data = new FormData();
data.append('msg', msg);
data.append('url', url + ' (at line ' + line + ', column ' + col + ')');
data.append('error', error.stack);
let xhr = new XMLHttpRequest();
xhr.open('POST', window.location.href);
xhr.send(data);
};
</script>
</body>
</html>
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