Optimal Website Performance in a Multi-Browser World

Website visitors have one expectation: outstanding Web experiences. Increasingly, the most critical determinant in delivering these experiences is a user's browser - of which there are many with complex applications, addons and serving multiple devices, to boot.

But the cost of failing to optimize browser performance and meet users' expectations has never been higher with a recent survey* finding that:

- 67 percent of users encounter a slow website a few times a week or more;
- 46 percent say slow load times cause them to abandon sites very frequently or somewhat frequently; and
- Over a third say slowness makes them less likely to return to a site.

Clearly, optimal browser performance is a key to keeping users on a website and, therefore, closer to conversion goals. But what is causing performance problems for so many users? Let's explore a few Web trends to find some answers:

Increased Browser Market Fragmentation: Microsoft's Internet Explorer 8 (IE8) is a very popular browser but with just 24 percent of the browser market share, it lacks the dominance of earlier versions of IE. Those earlier versions and other, competing options include Firefox, Safari, Chrome and others. In total, these options account for more than threequarters of all users.

Different browser platforms - as well as different versions of the same platform - perform and behave in different ways.

Consider connections per hostname: The greater the number of connections per hostname a browser can make, the faster a page loads. Currently there is an eight-second difference in response time between the fastest- and slowest-performing browsers. With such a wide variation, businesses must select performance optimization techniques suited to those browsers that drive the most traffic and revenue, on a global basis - an optimization technique that works well on one browser may cause an adverse effect on another.

Mobile Web Uptake: Today, businesses not only have to manage greater browser diversity on desktop computers but also contend with new complexity brought on by the mobile Web. With approximately 500 mobile browser/device combinations in use throughout the world, the prospect of managing performance across all (or even most) of them is seemingly impossible.

However, businesses that fail to optimize for the mobile Web experience could miss out on the sizable customer reach and revenue potential of this growing channel. For example, Morgan Stanley recently made a prediction that mobile users will outnumber desktop Internet users worldwide by 2014. Also consider the fact that AT&T has experienced a 50 percent increase in mobile data over the last three years. Despite this growth, users expect the mobile Web to load almost as quickly - if not faster - compared to the computer they use as home. Any business serious about the mobile Web must prioritize performance.

Feature-rich Applications Shift Responsibility to the Browser:
Today's websites and applications have evolved to rich composites; comprising of content and services delivered from the datacenter as well as from other sources outside the firewall - content delivery networks, advertising networks, video, shopping carts, Web analytics and ratings and review systems, for example. A recent study of 3,000 companies found that the average Web-based transaction involves 8.85 different third parties or hosts. The browser is responsible for assembling all of these components and presenting them to the user.

As applications grow richer (and by extension, heavier), technologies like AJAX, Flash and Flex help maintain application speed by enabling browsers to perform much of the application work. Other industry advances like HTML 5 place an even heavier burden on browsers by storing data on the client side, easing server demand. Browsers have evolved from a "rendering engine" to an "integration platform," and are responsible for over 60 percent of overall processing time, in some cases. For this reason, front-end performance improvements for key browsers often yield the highest payback for the user experience.

Below are a set of best practices for delivering superior performance across browsers to take control of your site and your users' experiences:

Implement a comprehensive monitoring approach, both pre- and post-deployment:
Businesses must monitor real-time performance on all major browser types available to users. Visual and functional testing should be automated and conducted on a regular basis. This approach should include both operational or synthetic monitoring of websites and applications across top browsers as well as experiential or real-user monitoring to capture what users and customers actually experience.

Today, worldwide testing networks offer businesses a fast, easy view into website and application performance across more than 500 browsers and browser/device combinations, from the real user perspective. This is important because as an application leaves the datacenter it is supplemented by thirdparty services and passes through local ISPs and mobile carriers before ultimately being delivered to browsers and devices. Problems can occur at any point of this Web application delivery chain, and the user perspective is the key to identifying problems, determining if they are browser-related (or not) and implementing optimization techniques at the browser level.

Understand which browsers your visitors use, and monitor what matters:
In an environment of limited resources, most businesses can't test and optimize across all browsers, so they must focus on the issues that really matter. If a company's major source of business comes from Asia, for example, it's far more important to measure site performance on IE6 - the most popular browser in that region - than the more recent, yet less used IE7 and IE8. Businesses should not waste energy on "edge cases," such as browser versions that represent insignificant portions of their audience. Instead, concentrate on monitoring browsers with the highest ROI potential for the business (the same rule applies to mobile browser/device combinations). Furthermore, businesses must concentrate on the parts of the website that matter most: The most popular content, highest revenue transactions and the most complex rich Internet applications.

Focus on front-end performance improvements: These efforts often deliver the most positive impact on user experience while requiring less time and money than back-end projects. Consider browser optimization techniques like domain charding, which entails "fooling" a user's browser into thinking there's more than one host. As a result, multiple connections can be made to a host server at the same time, enabling more objects to be downloaded simultaneously and thus creating faster downloads for little extra time or money.

However, domain charding is an example of an optimization technique that works well for some browsers but not others. It is ideal for older browsers that are typically capable of only two parallel connections at a time. In this scenario, if three hosts are detected, six objects (versus only two) can be downloaded at once. The technique is problematic for newer browsers like IE8 and Google Chrome that enable up to six parallel connections. For these browsers, three hosts detected translate into 18 images downloaded at once - which often overload servers and has the adverse effect of a Web performance slow-down.

Measure the impact of peak traffic:
Since newer browsers offer greater connection parallelism, businesses must understand how this can impact overall site performance under heavy load. Only then can they truly understand if their infrastructure capacity is sufficient. The key is to combine load generated from the cloud with load generated from real user desktops - providing a sense of how users are actually experiencing a website or application at the edge of the Internet, from their very browser. Older load testing approaches (which entail leveraging one's own datacenter-based servers to stimulate high traffic volumes) may miss the true impact of increased connection parallelism on the user's Web experience.

Browsers exert a huge influence on the quality of a user's Web experience. Ensuring performance across browsers and browser/device combinations is both essential and challenging. New approaches focused on the user's experience combined with a hierarchical prioritization of browsers (based on page views coming into a website) are the keys to overcoming complexity and maximizing Web performance, time and resources in a multi-browser world.

About the Author: Matthew Poepsel is VP of Performance Strategies of Gomez, the Web Performance Division of Compuware.

* "When Seconds Count", conducted by Equation Research on behalf of Gomez and released in September, 2010.