errors.js

(function() {
  window.onerror = function(message, url, line, column) {
    if (typeof url === "undefined" || url === null || url === "") {
      return;
    }

    var data = JSON.stringify({
      message: message,
      url: url,
      line: line,
      column: column
    });

    var xhr = new XMLHttpRequest();
    xhr.open("POST", "/i/js-error");
    xhr.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
    xhr.send(data);
  };
}());