Project: bom
Task (easy): Add pages 'docs/intro.html', 'docs/javascript.html', 'docs/css.html', 'docs/html.html', 'docs/nodejs.html' with random content about its filename. 'docs/intro.html' contains the links to other 4 pages. Add 5 options ('value' attribute format `docs/{name}.html`) for the above 5 pages to address select whose the first option value is 'docs/intro.html'. Change address option to display page in the content iframe. content iframe display the page from address select's first option value (default selected option).