Training Guide: Programming in HTML5 with JavaScript and CSS3 Ebook

Lesson 2: Handling storage events CHAPTER 15 565

1. Which of the following URLs can access data stored on http://www.example.com
   /lesson1/page1.html?
   A. http://www2.example.com/lesson1/page1.html
   B. http://www.example.com:8081/lesson1/page1.html
   C. https://www.example.com/lesson1/page1.html
   D. http://www.example.com/lesson2/page1.html
   E. http://example.com/lesson1/page1.html


2. What is the web storage limit currently recommended by the World Wide Web
   Consortium (W3C)?
   A. 4 KB
   B. 5 MB
   C. 500 MB
   D. 10 MB


3. What is the correct syntax for removing all values existing in localStorage?
   A. localStorage.clear();
   B. localStorage.removeAll();
   C. localStorage.abandon();
   D. localStorage.reset();


4. Which of the following storage mechanisms has the highest level of cross-browser
   support?
   A. Web storage
   B. Web SQL
   C. IndexDB
   D. FileSystem API


5. Which of the following features does web storage support?
   A. Indexing
   B. Transactions
   C. Asynchronous read/write
   D. Simple key/value pair storage

Lesson 2: Handling storage events

One of the biggest challenges you’ll face when working with web storage is keeping every-

thing in sync when a user has multiple tabs or browser instances open at the same time. For

example, browser tab one might have displayed a value it retrieved from localStorage just