Grasp the Fundamental Way in Which Convert Works
Once added, that code will send tracking requests to Convert servers and will receive back the testing data that needs to be available in order to run the test. More exactly, the backend servers would analyze the data received from the browser, would load visitor’s history, and based on that would decide which variation of a certain experience should present back.
convert._$(‘.buy_now’).val(“Add to Cart”);
The first part is the jQuery reference (which is made available on any page that has Convert Experiment’s code installed). The second part is just a basic jQuery function that will change the value of all the elements that have class buy_now (probably add to cart buttons) to Add to Cart.
Once the variation code is made available in the browser, element changes occur through a patented process which will poll the existence of elements and change them as soon as they are available, eliminating the flickering effect induced with the change.
On average sites that have Convert Experiences code installed before any other resource on the page (below <title>), the changes of elements according to the variation content occurs usually even before the full page is loaded. (An exception is Internet Explorer, for which the changes are done immediately after DOM Loaded event is fired).
As a conclusion, to be able to do A/B testing on your website, all that needs to be done is to add the Convert Experiences code in the head section, just after the <title> tag.