During any test, multiple network calls are exchanged between your website and VWO servers. VWO typically exchange the following calls:
Network Calls
Network calls are the ones that fetch the test settings on the current URL. These calls typically hold that data for the changes that need to be applied to the web pages. The following are the network calls used by VWO.
J.PHP |
Asynchronous VWO SmartCode makes this call-to-fetch test setting based on the current URL. It includes data of all the changes that need to be applied to the page and rendered to the visitor. The data format varies depending on the type of test that is running—A/B testing, Split URL, Multivariate testing (MVT), Visitor Analysis, Surveys, and so on |
JS_VISITOR_SETTINGS.PHP (Deprecated) |
Synchronous code makes this call-to-fetch test setting on the current URL. This call performs the same function as j.php does for Asynchronous code |
ACCOUNT_ID.js |
Serves all Test Campaign settings(Even if the Test campaign is not running on the page) along with the synchronous library with jQuery |
Library Calls
Library calls are a core component of VWO that reads and applies test settings. You can track goal conversions and attach different event listeners on the test pages. These calls are important to implement changes during an A/B, MVT, Personalization, and other test types. In the case of the Split URL test, the library redirects the URL to the variations. The following are the library calls used by VWO.
Va.js |
Asynchronous code makes this call to send information about the jQuery version used by VWO |
Vanj.js |
Asynchronous code makes this call to send information about the jQuery version used by your website |
tag-<random_number>.js |
The first tag call brings the library file, which is required to run test campaigns on your website |
tag-<random_number>.js |
The second tag call brings all the library files which are required to run non-test campaigns on your website |
Vis_opt.js(Deprecated) |
Synchronous code makes this call to send information about the jQuery version used by VWO |
Vis_opt_no_jquery.js(Deprecated) |
Synchronous code makes this call to send information about the jQuery version used by your website |
Pixel Calls
Pixel calls are the ones that track visitor actions, goal conversions, visitor settings timeout, etc.
L.gif |
This call is for visitor tracking. As soon as a visitor lands on your website and becomes a part of the test, l.gif comes into action |
H.gif |
This call is used to create a heatmap based on the visitor clicks on your website. As soon as a user clicks any part of the web page, h.gif is called. By default, in a single session, this call can be fired three times at the most. On the fourth click, h.gif won’t be fired.
NOTE: This call is exclusively for VWO Testing. |
C.gif |
This is the call that tracks goal conversions. Goal conversions are tracked only when the c.gif call is fired. This call contains the goal ID, which is unique to every goal in your test |
V.gif |
This call is for internal purposes and tracks unique visitors for an account. It also tracks the visitor settings timeout events |
s.gif |
This will be sent when a visitor gets sampled. Also, this is sent when any tag updates are required in the session, like a new goal or funnel is running |
analyze.js |
This is used to record visitor behavior for session recordings, heatmaps, and form analytics |
settings.js |
This call sends in the SPA application to fetch the new settings required for upcoming pages |
track.js |
This is the call to track user activities like key up, mouse move, scroll |