1. Exercise 12.4: Use a browser's developer tools to view the DOM tree of the document in Fig. 12.4. Look at the document tree of your favorite website. Explore the information these tools give you in the right panel(s) about an element when you click it. Please use the Chrome browser:

   1. Start with the documentation for Chrome Developer Tools: https://developers.google.com/web/tools/chrome-devtools/ (Links to an external site.)Links to an external site.
   2. CodeSchool has a free course on Chrome DevTools at https://www.codeschool.com/courses/discover-devtools (Links to an external site.)Links to an external site.

Write a paragraph or two about what you learned about using the Chrome developer tools.

2. Implement a web page that performs tip calculations. At a minimum, you will need an input element each for the original cost and for the tip rate, a button to trigger calculations, and an element for displaying the result. Use the DOM to access the elements in the web page. Do not use the prompt, alert, or document.writeln methods.