JS snippet to redirect errors to an alert (for debugging in Safari)

alerror.js

window.addEventListener('error', handleError, true);

function handleError(event) {
  if (event.message) {
    window.alert('error: ' + event.message + ' at linenumber: ' + event.lineno + ' of file: ' + event.filename);
  } else {
    window.alert('error: ' + event.type + ' from element: ' + (event.srcElement || event.target));
  }
}