We are committed to our customers’ site speeds and therefore proud to announce immediate availability of asynchronous code snippet for Visual Website Optimizer (VWO). This new code snippet has been months into development and refinement, and now we are first A/B testing vendor to come up with an asynchronous code snippet and are very excited about it! If you are a Visual Website Optimizer user, we highly recommend you to update your code snippet to new asynchronous one.
What is Asynchronous loading?
Essentially, instead of loading VWO code and your website sequentially, asynchronous code will load both in parallel, thereby speeding up your website load. See following graphic to understand it fully:
Advantages of Asynchronous code snippet:
- Fallback to control in case our servers are unavailable: in a rare and unlikely case our servers are unresponsive or take some time to respond, a timeout will happen and your original page will be shown. As history shows, even though it is rare, due to network unavailability or DDOS attacks, even best networks and servers can become unresponsive. The asynchronous code snippet has a timeout setting (default is 2 seconds, but is configurable — see below), and if our servers or Content Distribution Network (CDN, currently Amazon’s Cloudfront) don’t respond within that time, your normal page will get displayed.
How to get Asynchronous code?
Login to your Visual Website Optimizer account, and go to ‘Get Tracking Code‘ section (under Tools tab).
Settings available in Asynchronous code
In code snippet, you will find two variables that you can adjust (although we recommend keeping default values intact).
- settings_tolerance=2000 this is the maximum time (in milliseconds) for which the code snippet will wait for test settings to arrive from our servers. If no settings arrive within this period, timeout will happen and your original page will get displayed (test won’t run in this case, as fallback has happened).
Note that in normal circumstances, all the data and files that need to be download will get downloaded in 100-200 milliseconds, so the timeout is an absolutely maximum threshold and can safely be kept as it is.
If you decrease the threshold, one side effect of it would be that some visitors (with slower connections or with have local ISP/network issues) may not be able to become a part of your test (because timeout occurred for them), so you may potentially lose some visitors or conversions registered in your A/B test.
Compatibility of Asynchronous code snippet
Highly recommended: use new Asynchronous code
Because of numerous advantages of new asynchronous code snippet, we highly recommend you to start using it as soon as possible. In case you have any questions or suggestions, please feel free to contact us at firstname.lastname@example.org