| Selenium RC
||Selenium Web driver
||WebDriver on the other hand tries to control the browser from outside the browser. It uses accessibility API to drive the browser. The accessibility API is used by a number of applications for accessing and controlling applications when they are used by disabled users and is common to web browsers.
|With Selenium RC the New Browsers will be supported easily
||Web Driver interacts with page elements in a more realistic way.
|Selenium RC cannot support the headless HtmlUnit browser. It needs a real, visible browser to operate on.
||Web Driver can support HtmlUnit browser.