The retailer uses a data URI scheme for streamlined loading, Keynote Systems says.
Bill Siwicki , Managing Editor, Mobile Commerce
Retailers who know the tricks of the web programming trade can do well in mobile commerce site performance. Developers who know how to make effective use of sprites, for example, can speed page load times. A sprite is a programming tool that enables a developer to package multiple images in one file, which thus requires only one server request, not a request for each image.
The technique of the week is a data URI scheme, as successfully deployed by Victoria’s Secret Direct, which jumped from No. 26 to No. 13 on the Keynote Mobile Commerce Performance Index last week. The merchant’s m-commerce site home page loaded on average in 4.82 seconds and did so completely and successfully 98.92% of the time. Those figures weighted and combined earned the retailer an index score of 715 out of 1,000.
URI stands for universal resource identifier, a string of characters used to identify a web resource such as an image. Data URI is a scheme of encoding data within a web page that make up page elements such as images or Cascading Style Sheets, a mark-up language used to define pages and denote where elements appear on a page. With multiple elements encoded within a page, no extra HTTP server request is made to fetch the embedded elements as opposed to a request for each element. CSS sprites might be challenging for the average developer because the developer must combine numerous images into a single sprite image file; with data URI, a developer can keep images separate atop an HTML file, Keynote Systems Inc. says.
The data URI technique helped Victoria’s Secret improve its mobile site performance. “The m-commerce site home page loads 15 elements, keeping the page size less than 50 kilobytes. The site also implements data URI schemes for navigation image icons, which reduce the number of HTTP server requests,” explains Venkatesh Giri, mobile performance evangelist at Keynote Systems. “CSS sprites require users to combine their images into a single large sprite image, which is later fetched by one extra server request. Instead of using an extra request to get the large sprite image, data URI schemes use zero extra requests to fetch the images as the images are embedded directly into HTML and CSS files—there’s no need to combine all the images into a single large image file. This solves the same problem, dealing with multiple images, in a much more elegant and maintainable way.”
Victoria’s Secret can improve its performance further by eliminating page redirects, Giri adds. The VictoriasSecret.com home page contains four redirects. This is a process that can be done with one redirect. “Reducing the number of redirects would significantly decrease the home page load times and likely place this retailer into a top five position,” Giri says.
Victoria’s Secret, No. 23 in the Internet Retailer Mobile Commerce Top 300, did not immediately respond to a request for comment.
Office Depot Inc. came in first last week with a load time of 2.71 seconds and a success rate of 99.68% for a score of 955. Buy.com came in second with a load time of 3.68 seconds and a success rate of 99.79% for a score of 940. And HSN Inc. came in third with a load time of 4.58 seconds and a success rate of 99.79% for a score of 905.
The index average load time was 7.45 seconds, the average success rate was 99.34% and the average score was 701.
Office Depot is No. 53 in the Internet Retailer Mobile Commerce Top 300. Buy.com is No. 19 and HSN is No. 58.
Click here and then click on Keynote Mobile Commerce Performance Index Part 1 and Part 2 to see this week’s complete results for all 30 retailers on the index.
Keynote Systems measures 30 representative m-commerce sites exclusively for Internet Retailer. The sites include merchants in multiple categories and channels, and of multiple sizes, ranging from such giants as Amazon.com Inc. to midsized retailers like Toolfetch.com LLC. Keynote tests the sites in the index every hour Monday through Sunday from 8 a.m. through midnight Eastern time, emulating three different smartphones on three different wireless networks: Apple Inc.’s iPhone 4 on AT&T, the HTC Evo on Sprint and the Droid X on Verizon. The HTC Evo and the Droid X run Google Inc.’s Android operating system. Keynote runs the tests in New York and San Francisco.
Keynote combines a site’s load time and success rate, equally weighted, into a single score. Given that both performance and availability are important, the score reflects the overall quality of the home page; a higher score indicates better performance. Scores also reflect how close sites are to each other in overall quality. The index average score is the midpoint among all the sites’ scores.