Proper Web Site Testing - Browser Testing

by Craig Mazur - Copyright 2004-2007 - All Rights Reserved

April 12, 2004 Updated: July 14, 2007

Part 1 - Internet Connection Speed
Part 2 - Browser Testing
Part 3 - Web Page Validation

The browser testing problem

Browser testing can be a serious annoyance due to inherent incompatibilities between Microsoft's Internet Explorer (IE) and Mozilla's FireFox, further incompatibilities between different versions of the same browser, as well as numerous bugs that were never fixed in some versions. This situation is the result of many years of "Browser Wars" where Microsoft and Netscape jockeyed for the top position. Each introduced a number of new features that were not always recognized by the other, and both companies were guilty of frequently ignoring the established standards in favor of their own standard-setting desires.

Today, Mozilla's FireFox has replaced Netscape as the second most popular browser. But differences between the two still remain. This is most evident when using tableless web page designs, or any heavy use of CSS.

By any measure, Microsoft won the original war with Netscape, but FireFox quickly replaced it and has gained about a 15% market share for browsers. Regardless of which browser you prefer to use, your visitors may prefer another, so it is important to at least test all web pages with the two most popular browsers.

Determining which browsers your customers are using

The easiest way to determine which browsers you should use for testing is to examine your server logs using whichever log analysis software your hosting company provides. Almost all hosting companies offer log analysis software and you should make sure that any hosting company you use does offer this benefit.

Every time a user requests a Web page, the server records the request in a log file. Along with the name of the requested file and other details, the server records the browser type and operating system that is making the request. This information is compiled and displayed through log file analysis software. To make sure that your testing covers the browsers your customers use, make a list of the most popular browsers found in the log files.

Finding old versions of browsers

There are a few Web sites that archive the older versions of browsers and make them available for testing purposes. The following is one popular sources for old browser versions:

Evolt.org Browser Archive

Installing multiple versions of a browser on a single PC

Because Internet Explorer is integrated with the operating system on PCs using Microsoft operating systems, it is difficult to cleanly install multiple versions of the IE browser. If you need to test with multiple versions of IE, the best solution is to install each version on a separate PC and turn off the automatic update feature found in newer Microsoft operating systems so that the installed version does not get replaced with a newer version. Be aware that this does leave some security holes wide open, so if you have concerns in this area, do all of the Microsoft updates manually, including browser security patches. Just don't allow a PC with an older version of a Microsoft browser to be upgraded to the newer browser. At the time of this writing, the only two versions of IE that you need to test with are IE 6 and IE 7. You will need to test with both of these browsers because each treats some CSS rules differently.

FireFox has always been much more stable and doesn't exhibit the same rendering issues among different versions, so it is usually pretty safe to test with the most current version of FireFox. You can find the most current version of FireFox at the Mozilla web site.

What about Macintosh testing?

Graphic artists and Web site designers seem to love Apple's Macintosh computers. In fact, they are probably the primary reason that Apple continues to exist as a PC manufacturer. But if you use a Macintosh for design work, recognize the cold fact that 99+% of Internet users are using PCs. You will therefore need to test using a PC. There are inherent differences between a Web page rendering on a PC and one on a Macintosh. Colors are slightly different, images display darker on a PC, screen resolutions are different and the recognition of some HTML tags is different. You therefore absolutely need to test using a PC. Likewise, if you develop Web sites on a PC and your server logs indicate that a significant percentage of your customers are utilizing Macintosh computers, you should set up a Macintosh with the appropriate browsers for testing.

Remember to clear the cache before testing

Modern browsers cache (store) HTML, images, JavaScript and CSS files and use those files to speed up rendering the next time a page is requested. You must therefore clear the browser cache before you begin each Web site test. This assures that you will experience the same rendering performance as a first-time visitor.

To clear the cache with Internet Explorer:

Select Internet Options from the Tools drop-down menu
On the General tab, click the Delete Files button
Click the OK button in the Delete Files window
Click the OK button to return to the browser window
Click the refresh button

Internet Explorer offers an additional feature that clears the cache every time you shut down the browser. To turn this feature on, first make sure the cache is clear using the procedure listed above. Next, select the Tools menu from the toolbar, select Internet Options, select Advanced, and scroll down to the Security section and make sure that "Empty Temporary Internet Files when Browser is Closed" is checked. If you check it, make sure to click OK.

To clear the cache with Mozilla's FireFox

Click Tools on the top menu
Select Options
Select the Privacy tab
Make sure that "Always clear my private data when FireFox closes" is checked.
Click on the Settings button
Make sure that saved passwords and cookies are unchecked
Click OK on the Settings dialog box
Click OK on the Options dialog box
Click the Reload button on the browser window

Browser compatibility testing services

There are a few services--some free and some by subscription--that provide simulations of various browser renderings. These services can be useful for identifying rendering problems due to browser incompatibilities. You can find them by searching for "browser compatibility testing". Here are a few popular choices:

NetMechanic's Browser Photo A subscription service that simulates a wide range of browsers.

iCapture Service that simulates Apple's Safari browser.

Part 1 - Internet Connection Speed
Part 2 - Browser Testing
Part 3 - Web Page Validation

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