Javascript Title Get

title.js

function callback(title) {
  console.log(title);
}

function getTitle(url, callback) {
  var title = '';
  var xhr = new XMLHttpRequest();
  xhr.open('GET', url, true);
  var end = false;
  xhr.onreadystatechange = function() {
    if (xhr.readyState === 4 && xhr.status === 200) {
      var htmlText = xhr.responseText;
      title = htmlText.slice(htmlText.indexOf('<title>'), + 7, htmlText.indexOf('</title>'));
      callback(title);
    }
  }
  xhr.send(null);
}

getTitle('https://www.google.com', callback);