Testing can be conducted sequentially or in parallel. In sequential testing, often the easiest to implement, the various versions of the webpages are made available online for a specified time period. In parallel (split) testing, both versions are made available, and the traffic is divided between the two. The results of sequential split testing can be skewed by differing time periods and traffic patterns in which the different tests are run.
In marketing automation, Ryan Deiss, co-founder of Digital Marketer, often describes the sales funnel as a multi-step, multi-modality process that moves prospective browsers into buyers. It's multi-stepped because lots must occur between the time that a prospect is aware enough to enter your funnel, to the time when they take action and successfully complete a purchase.
The first helps direct attention to the goal of the page -- for you to fill out the form -- in a way that's unobtrusive and feels less like a chore. The second gives this page an SEO boost (search engines will have more content to crawl) and assuages any worry from folks who need to know more about a piece of content before handing over their information, all while not distracting people from the chat window.