Seconds Count: All About Web Performance

Matt Young
by Matt Young 20 Apr, 2016

Top websites across multiple industries are failing user expectations, Radware found in its latest report, 2016 State of the Union: Multi-Industry Web Performance (Desktop Edition).


Analyzing the top 50 websites in each of the ecommerce, news, travel and sports categories, Radware found evidence of page bloat and spiraling complexity. The result is slow load times that often force users to wait more than three seconds - the attention threshold for most visitors - to interact with a website's key content, or Time to Interact (TTI).


Multiple studies have found that a whopping 57 percent of users will abandon a website after that three-second window has passed, leaving behind any potential purchases, subscriptions or impressions. Not to mention that slow sites damage the customer relationship and result in significant lost revenue.


Putting a finer point on it, assuming a conversion rate of two percent and an average spend of $115 per person, as the Centre for Retail Research estimates, a site that gets 100,000 visitors a day would lose over $130,000 a day if 57 percent of its visitors bounced from frustration over slow loading.


With so much at stake, it's critical to identify the culprits to ensure a better web-wide experience for site users.


Sites are rendering feature content too slowly


While the research showed that the load times and the TTI varied by industry, all four categories were missing the three-second target users expect.


  • Ecommerce sites had a median size of 1.4 MB, had 97 requests, and a TTI of 3.1 seconds.
  • News sites were slightly larger than ecommerce sites at 1.6 MB, had 122.5 requests, and a TTI of 4.1 seconds.
  • Travel sites weighed in at 3.3 MB, had 92 requests and tied news sites in their TTI of 4.1 seconds.
  • Sports sites' bulky median size of 4.2 MB was accompanied by a median of 148 requests and a disappointing median TTI of 5.2 seconds.

The best-performing category was ecommerce, with 48 percent of the tested sites landing at three seconds or less.


News sites were middling, with 22 percent in the green, followed by travel sites, with 20 percent meeting the three-second target or better, but 28 percent of those sites exceeded six seconds for their TTI - double the expected time and well within the danger zone for site abandonment.


The sports category fared the worst, however: Only 6 percent of the sites tested were below three seconds, with 34 percent exceeding six seconds. In fact, the slowest site tested had a TTI exceeding 10.8 seconds, with 480 requests.


Page composition and optimization levels vary by industry


With the four sectors, nuances in page composition were expected, and there were - different websites are built for different purposes. As the above results show, each category performed differently based on its composition, but this was also due to how effectively web performance optimization (WPO) best practices were followed.


Typically, images are a key component of transactional sites. This is especially true for ecommerce and travel, although JavaScript can end up being used heavily where there are forms to be filled out, including product searches or where consumers are looking for information on travel packages.


Images were the number one reason for the slowdown in the sports category, and they played a major role in the news sites that had a more tabloid-style layout.


Radware found the page composition of the median sites to be relatively varied among the categories:

  • Ecommerce: 81 percent of requests were images, 8.6 percent for JavaScript. The page weight was 80.2 percent images and 13 percent JavaScript - pretty proportional.
  • News: 58.3 percent of the requests were for images, 25.2 percent for JavaScript. However, the JavaScript requests accounted for 38.7 percent of the page weight, with images sitting at 41.1 percent.
  • Travel: 59.2 percent of the requests were for images, 29.6 percent for JavaScript. The footprint was 54.6 percent from images and 32.9 percent JavaScript.
  • Sports: 74 percent of the requests were for images, and only 5.98 percent for JavaScript, but those JavaScript requests made up 31.3 percent of the total page weight, with 53.9 percent coming from the image requests.

For any site, whether the composition rests more on images or scripts, optimization is key. Properly formatting and compressing images will reduce the page's footprint and load time, and limiting JavaScript and redirects will improve page speed, as will minifying code, which is essential to keep things moving.


Most sites failing to employ core image optimization techniques


Across all four verticals researched, a majority of websites don't use core optimization techniques.

As noted earlier, each industry featured websites with a different spread of resources, from images to HTML, JavaScript and other elements. But the bulk of all the content was images, which generally make up 50 to 60 percent of a page's weight.


The WebPagetest tool generates grades based on multiple Web performance criteria, among them image compression. In testing the sites, Radware found only a small minority of sites from each category are getting an "A" from WebPagetest:


Image compression is a core performance technique that minimizes the size (in bytes) of a graphics file without degrading the quality of the image to an unacceptable level. Reducing an image's file size has two benefits:


  • Decreasing the amount of time required for images to be sent or downloaded.
  • Increasing the number of images that can be stored in the browser cache, thereby improving page render time on repeat visits to the same page.

Compressing image files lightens a Web page's overall payload, and fewer bytes mean reduced bandwidth and faster pages. All sites would benefit by adopting image optimization best practices.


The case for an automated WPO solution


Hand-coding pages for performance is specialized, time-consuming work, particularly on highly dynamic sites that contain hundreds of objects per page, as both browser requirements and page requirements continue to develop.


Automated front-end performance optimization solutions apply a range of performance techniques that deliver faster pages consistently and reliably across the entire site, from image optimization to object deferral, and reduce the number of server requests.


However site owners decide to tackle Web performance, sites can be fine-tuned to serve up a better experience. If not, users will take their Web traffic, dollars, bookings and impressions elsewhere.