Multivariate testing is the form of AB testing specifically employed in ecommerce industry. Using Multivarient Testing, we can determine effect of two variations on conversion or similar business goals.

Have a look at Wiki Reference

3rd Party Solution:

Optimizely is a great tool and lets you compare two variations within your website without producing two variations separately. It inserts a single snippet of javascript into the website and depending upon our required changes, it pushes different variations of the page to different users and keeps tracking outcome of those variations in real time. Thumbsup I must say.

Google Analytics:

In Google Analytics, multivariate testing is called Split Testing or Content Experiments.

Multivarient Testing explained on