Asda is a Leeds-based British supermarket chain that is present in over 633 locations and employs over 145,000 people
A speed report from Lighthouse paints a rather grim picture and scores the Asda website 7 seconds on the speed index (SI), and 17 on Performance.
There are many reasons why the Asda website is so slow. This includes:
- Bloated JavaScript files
- Unused CSS files
- Absence of lazyloading
- Unnecessarily large image files
- Old Image formats
- Render-blocking resources
Let’s look at each of these reasons and identify potential ways that Asda can make its website load faster.
But before we do that, a quick word about our website CWVIQ.com - we are a free email alert service that sends out notification any time your website is loading very slowly (often due to heavy traffic, or poor scripts). If you have a website, consider setting up an alert so that you can fix issues before they become major. Bloated JavaScript files
Asda uses a lot of JavaScript to run the website. However, loading them all from one source could slow up the performance of the website. Asda can avoid this by splitting the code into smaller files. This way, you only load files that are necessary.
The Asda website can be as much as 1.2 seconds faster by adopting this technique.
Unused CSS files
Asda uses CSS files to load the styling elements for the website. However, this file contains a lot of unused scripts that can be slowing down page loading by as much as 0.15 seconds. Code splitting may help avoid this issue.
Absence of lazyloading
Images and videos are by far the most resource-intensive assets and take up a lot of bandwidth during the page-loading process. This can be a real problem on shopping websites since they typically include a lot of graphical content.
But here is the thing – a user who visits the website is not going to need all the images on the page to load. Instead, they only need those images on the top fold of the website to load. The rest can be ‘lazy-loaded’ – that is, they can be loaded after all the other critical components of the webpage have completed loading.
The Asda homepage can load as much as 0.75 seconds faster if images were lazyloaded.
Unnecessarily large image files
Another common problem that users face – especially when they access the website while on the move – is having to load unnecessarily large image files that are not optimized for the mobile phone. Not everyone has access to WiFi at all times. Loading oversized product images is unnecessary.
According to the Lighthouse estimate, the Asda website homepage can load 2.55 seconds faster if it made all the images more cellular-data-friendly.
Old Image formats
The Asda website uses a lot of JPG and PNG files that are considered outdated and heavy for modern web use. Replacing them with WebP and AVIF files can save as much as 4.5 seconds from the page loading time.
Render-blocking resources
There are scripts on the Asda website that need to run first before they let the rest of the code be executed. The render-blocking resources issue can shave off around 0.89 seconds from the loading time for the Asda website.
How do you avoid this? If the script is not critical, avoid having it in the <head> tag of your HTML code. But if you do need to have it there for some reason, make sure to include the defer or async attribute so that they do not block the loading of other resources.
Anand Srinivasan is the founder of CWVIQ, and has been in the internet media space for over 15 years. He has previously served as the AVP of Products and Head of Business at popular media portals. He has worked with several SaaS and enterprise businesses as an external consultant for their SEO marketing campaigns.