HtmlUnit is a headless web browser

Web browser

A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

 written in Java

Java (programming language)

Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...

. It allows high-level manipulation of website

Website

A website, also written as Web site, web site, or simply site, is a collection of related web pages containing images, videos or other digital assets. A website is hosted on at least one web server, accessible via a network such as the Internet or a private local area network through an Internet...

s from other Java code, including filling and submitting form

Form (web)

A webform on a web page allows a user to enter data that is sent to a server for processing. Webforms resemble paper or database forms because internet users fill out the forms using checkboxes, radio buttons, or text fields...

s and clicking hyperlink

Hyperlink

In computing, a hyperlink is a reference to data that the reader can directly follow, or that is followed automatically. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks...

s. It also provides access to the structure and the details within received web page

Web page

A web page or webpage is a document or information resource that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a monitor or mobile device. This information is usually in HTML or XHTML format, and may provide navigation to other web pages via hypertext...

s. HtmlUnit emulates parts of browser behaviour including the lower-level aspects of TCP/IP and HTTP. A sequence such as getPage(url), getLinkWith("Click here"), click allows a user to navigate through hypertext

Hypertext

Hypertext is text displayed on a computer or other electronic device with references to other text that the reader can immediately access, usually by a mouse click or keypress sequence. Apart from running text, hypertext may contain tables, images and other presentational devices. Hypertext is the...

 and obtain web pages that include HTML

HTML

HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....

, JavaScript

JavaScript

JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....

, Ajax

Ajax (programming)

Ajax is a group of interrelated web development methods used on the client-side to create asynchronous web applications...

 and cookies

HTTP cookie

A cookie, also known as an HTTP cookie, web cookie, or browser cookie, is used for an origin website to send state information to a user's browser and for the browser to return the state information to the origin site...

. This headless browser can deal with HTTPS security, basic http authentication, automatic page redirection and other HTTP headers. It allows Java test code to examine returned pages either as text, an XML DOM, or as collections of forms, tables, and links.

The most common use of HtmlUnit is test automation

Test automation

Test automation is the use of software to control the execution of tests, the comparison of actual outcomes to predicted outcomes, the setting up of test preconditions, and other test control and test reporting functions...

 of web pages, but sometimes it can be used for web scraping

Web scraping

Web scraping is a computer software technique of extracting information from websites...

, or downloading website content.

Version 2.0 includes many new enhancements such as a W3C DOM

Document Object Model

The Document Object Model is a cross-platform and language-independent convention for representing and interacting with objects in HTML, XHTML and XML documents. Aspects of the DOM may be addressed and manipulated within the syntax of the programming language in use...

 implementation, Java 5 features, better XPath

XPath

XPath is a language for selecting nodes from an XML document. In addition, XPath may be used to compute values from the content of an XML document...

 support, and improved handling for incorrect HTML, in addition to various JavaScript enhancements, while version 2.1 mainly focuses on tuning some performance issues reported by users.

See also

• Headless system
  Headless system
  A headless system is a computer system or device that has been configured to operate without a monitor , keyboard and mouse...
  
  
• Web scraping
  Web scraping
  Web scraping is a computer software technique of extracting information from websites...
  
  
• Web testing
  Web testing
  Web testing is the name given to software testing that focuses on web applications. Complete testing of a web-based system before going live can help address issues before the system is revealed to the public...
  
  
• SimpleTest
  SimpleTest
  SimpleTest is an open source unit test framework for the PHP programming language and was created by Marcus Baker. The test structure is similar to JUnit/PHPUnit...
  
  
• xUnit
  XUnit
  Various code-driven testing frameworks have come to be known collectively as xUnit. These frameworks allow testing of different elements of software, such as functions and classes...