Code to get title may not result in error

The code that checks for the title in the returned AJAX data may result in a JS error. Attached is a patch to help with that, but it does set it to a blank title if one is not found. Not sure on the best thing to do as the default?

// get title of loaded content.
var matches = data.match("<title>(.*?)</title>");
if (matches) {
  // -- NOTE --
  // Title is defined here, within the if statement
  // -- END NOTE --

  // Decode any HTML entities.
  var title = $('<div/>').html(matches[1]).text();
  // Since title is not changing with window.history.pushState(),
  // manually change title. Possible bug with browsers.
  document.title = title;
}
// store current url.
window.history.replaceState({page : 0} , document.title, window.location.href);

// -- NOTE --
// Title is used here, outside of if statement
// -- END NOTE --

// Change url.
window.history.pushState({page : 1} , title, url);