PhantomJS is a new solution that provides headless testing of web applications. It is also a tool for dynamically capturing and rendering pages as images. It allows you to programmatically manipulate page content to control and change it to different forms. It can scrape websites and save important information to files. It will also provide you network-level information of your page and site resources. These are just a few of the functions that PhantomJS can do for us. It provides a fresh and a whole new way for web designers, testers, and developers to perform and create browser-based solutions.
PhantomJS uses QtWebKit as its core browser capability and uses the WebKit JavaScript engine for script interpretation and execution. Anything and everything that you can do in a WebKit-based browser (such as Chrome, Safari, and Opera browser) you can do with PhantomJS. It's more than just a browser because it supports web standards, such as CSS selector, DOM manipulation, JSON, HTML5 Canvas, and SVG; moreover, you can do some cool stuff such as performing file system I/O, accessing system environment variables, or even instantiating your own implementation of a web server daemon.
Before we go through the features of PhantomJS, first we need to get our copy of the PhantomJS binaries. Typically, PhantomJS provides downloadable releases of binaries that are precompiled and packaged. You can choose from Linux, Mac OS X, and Windows precompiled packages. To download a copy, go to http://www.phantomjs.org/download.html.
Download your binaries based on your preference of operating system. After downloading, extract the binaries to any folder you desire. That's it! Your PhantomJS binary is ready to be used.
We will be using the Mac OS X version of PhantomJS throughout this book for running code examples. Don't worry if you are working on a different platform; the instructions are the same on all platforms.
Tip
Quick PhantomJS install on Mac OS X
As an alternative to downloading the precompiled binary, we can install PhantomJS using brew:
brew update && brew install phantomjs
For more information about brew, visit http://brew.sh/.