Desktop App and Add-on Developers, Beware of Browser Changes
If you make add-ons such as toolbars, extensions or other plug-ins for web browsers, you’ve probably noticed an increasing number of obstacles when trying to make your products work on the growing number of platforms that are out there. While browser add-ons provide many useful functions, such as search and quick access to specialized content, they can also be the source of problems such as long load times and program crashes. In response, the major browser makers have started making it harder for users to install add-ons, by adding additional consent screens and alerting them to long
load times. As an add-on distributor, you should be aware of these changes and the challenges they pose.
Know the Market
It used to be that Internet Explorer was by far the dominant web browser, but these days several other browsers such as Firefox and Chrome have increased market share significantly. Statistics vary and you may find different results depending on your audience, but the top 3 browsers are growing closer in market share, as Internet Explorer continues to lose users to Firefox, Chrome and even Safari. In October, 2011, technology site ars technica recently reported that Internet Explorer dropped below the 50% mark across all operating systems.
Other sites such as w3schools.com and Wikipedia give Internet Explorer an even smaller share so it is a good idea to track and monitor which browsers are more common among your users. A low reading with a particular browser can also indicate a problem with your add-on.
Usage is even more splintered when taking browser version into account. Internet Explorer remains split between the last 4 major versions while Firefox is even more spread out. By contrast, most Chrome users are using the latest version because Chrome updates automatically.
Some of the top browser makers are increasing the frequency of updates. Mozilla announced earlier this year that it will move to a rapid release cycle, with new versions coming every 6 weeks. This is similar to Google’s release cycle for
Chrome. Meanwhile Microsoft appears to be sticking with a longer release cycle for Internet Explorer, with version 10 expected early in 2012.
Recent Browser Changes
Internet Explorer 9 and Firefox 8 both introduced new confirmation prompts when add-ons are installed. This change raises a barrier for add-on distributors such as W3i’s InstallIQ. Although users go through the process and consent to install an add-on, they must consent again to accept the add-on the next time they use their browser.
IE9 displays an information bar at the bottom of the screen, and it may not be apparent to the user that it is there. Some users may miss it and after a few times IE will stop showing the bar and simply disable the add-ons. IE9 also added an Add-on Performance Advisor, which alerts the user when add-on load times exceed a certain threshold.
Firefox 8 has two types of add-on confirmation depending on how the add-on is installed. If you install your add-on using the common method of copying files into the Firefox extensions folder, then the confirmation prompt will open in a new tab when the browser is restarted. This prompt includes a checkbox which is unchecked by default, and is easily skipped by the user. Even worse, if multiple add-ons have been installed, Firefox will open multiple tabs, but as soon as one add-on is accepted, Firefox prompts the user to restart. Upon restarting, Firefox loses the other pending add-ons. This is a
significant barrier to installation processes that may install more than one add-on, such as InstallIQ.
Fortunately there is another method you can use, which should yield a higher rate of add-on enablement. You can package your add-on in an XPI file and install it on the Firefox command line. An XPI file is a Zip file containing the add-on components and an XML manifest. When add-ons are installed using the XPI method, Firefox displays a modal dialog with an “Install Now” button which is much more likely to be accepted by the user. In addition, multiple add-ons can be combined into a single install, with a single prompt to enable all of them.
InstallIQ now requires add-on partners to package their add-ons in XPI files so we can better manage the installation process. InstallIQ will automatically combine multiple XPI’s and install them by launching Firefox.
Looking Ahead
With browser updates coming at a faster rate and add-on installations becoming increasingly difficult for the user, it is important to keep an eye on forthcoming changes and be prepared to adjust your products. Mozilla makes future Firefox releases available as they are being developed. They have a Beta channel for the next scheduled release, and the Aurora channel for changes that are further out.
Similarly, Google has multiple release channels which you can install for various platforms.
Meanwhile Microsoft is providing a preview of Internet Explorer 10. Microsoft has said that the Metro version of IE10 will not allow any add-ons, although the desktop version will.
Regardless of the nature of your add-on, it is more important than ever to streamline your development process and be ready to quickly make changes to adapt to the ever-changing browser platform.
Bill Zitomer, Software
Development Team Lead, W3i, LLC
Bill uses his over twenty years’ experience to build W3i’s core desktop products as well as back-end technologies.








