At this point, if the page being displayed in Chrome contains any person microdata, we'll have an array containing one or more objects that contain the microdata and the text it describes. In this task we'll allow the user to store that data if he/she wishes.
Because our content script runs in the context of a web page and not our extension, we'll need to use messaging once again to pass any gathered data back to the extension for storage.
In order to set up messaging between our content script and the extension, we'll need to add a background page. A background page runs continuously while the extension is installed and enabled and will allow us to set up handlers to listen and respond to messages sent from the content script.
Background pages may be HTML or JavaScript. In this project we'll use the JavaScript version. Create a new file now and save it in the chrome-extension directory as background.js. We also need to register...