JQuery

I am reading "A Software Engineer Learns HTML5, JavaScript, and JQuery". The examples for using JQuery in Chrome under the Tools->Javascript Console did not work at first. It was a simple fix: Include a script at the top of the HTML file with

src="http://ajax.googleapis.com/ajax/libs/jquery/2.0.3/jquery.min.js"

or something similar. This particular line reads the library from Google. It can also be downloaded from:

jquery.com/download