Figure 17-12. http://www.google.com
Google is known for its simple and fast page design. Its home page, http://www.google.com, is just 18K in total page size and issues just 3 HTTP requests (the HTML document and 2 images). However, even in this simple page there are several performance optimizations worth noting.
The Google page is just three HTTP requests, but Figure 17-13 shows five HTTP requests.
Figure 17-13. Google HTTP requests
The two extra requests aren't really part of the page. One is http://www.google.com/favicon.ico (see Figure 17-14). Favicons are used to associate a visual image with a URL. They are displayed next to the URL at the top of the browser, next to each URL in the list of Bookmarks or Favorites, and in tabs (for tab-enabled browsers). Browsers fetch them the first time a web site is loaded. If a web site doesn't have a favicon, a default icon is used.
Figure 17-14. http://www.google.com/favicon.ico
The second extra request is for http://www.google.com/images/nav_logo3.png, shown in Figure 17-15. This is a CSS sprite, a combination of images that was described in Chapter 3. I say it is not part of the page because it is loaded after the page is done, as part ...