A headless browser, a browser without any kind of graphical user interface (GUI) provides computerized control of a web page in an environment alike to popular web browsers but is performed through a command-line interface or managing network communication. They are especially useful for examining web pages as they can render and understand HTML the very way a browser would, including styling components such as page layout, color, font selection and execution of JavaScript and AJAX which are usually not possible when using other testing methods.
