This recipe provides a strategy for automatically loading a web page at different viewport sizes, capturing screenshots at each size, and thus testing our responsive design's breakpoints.
To run this recipe, we will need a script that accesses a web page; the target URL will need to be a responsive design with several breakpoints or viewport targets that we want to test. We also need write permissions to the filesystem in the script's working directory.
The script in this recipe is available in the downloadable code repository as recipe07.js under chapter07. If we run the provided example script, we must change to the root directory for the book's sample code.
Lastly, the script in this recipe runs against the demo site that is included with the cookbook's sample code repository. To run the demo site, we must have Node.js installed. In a separate terminal, change to the phantomjs-sandbox directory (in the sample code's directory), and start...