// Saves options to chrome.storage.sync.
 function save_options() {
   var username = document.getElementById('username').value;
   var password = document.getElementById('password').value;
   chrome.storage.sync.set({
     username: username,
     password: password
   }, function() {
     // Update status to let user know options were saved.
     var status = document.getElementById('status');
     status.textContent = 'Options saved.';
     setTimeout(function() {
       status.textContent = '';
     }, 750);
   });
 }
 
 // Restores select box and checkbox state using the preferences
 // stored in chrome.storage.
 function restore_options() {
   // Use default value color = 'red' and likesColor = true.
   chrome.storage.sync.get({
     username: '',
     password: ''
   }, function(items) {
     document.getElementById('username').value = items.username;
     document.getElementById('password').value = items.password;
   });
 }
 document.addEventListener('DOMContentLoaded', restore_options);
 document.getElementById('save').addEventListener('click',
     save_options);