catch and log javascript errors to your server with no dependancy on 3rd party libs

js_log_errors_to_server.js

window.MaximumErrorCount = 5; // Limit number of errors sent

// register error handler
window.onerror = function(errorMsg, file, lineNumber) {
  window.errorCount = window.errorCount || 0;
  window.errorCount++;

  if (window.errorCount <= window.MaximumErrorCount) {
    var request = new XMLHttpRequest(); // OK for IE8+
    request.open('POST', '/jsError.php', true); // POST to URL
    request.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
    request.send({
        errorMessage:   errorMsg,
        file:           file,
        url:            window.location.href,
        lineNumber:     lineNumber,
        ua:             navigator.userAgent
    });
  }
}

jsError.php

<?php
// Do something more robust in production to check it's a valid post etc
// also use Monolog or similar to log, but hey this is an example :)

$logMessage = sprintf(
  'JS_ERROR[%s] URL[%s] on file[%s:%s] UA[%s]',
  $_POST['errorMessage'],
  $_POST['url'],
  $_POST['file'],
  $_POST['lineNumber'],
  $_POST['ua']
);
error_log($logMessage);