Now I am learning a great deal just by debugging the code. However this is a painful process. JavaScript is case sensitive. So if you declare a variable with one spelling, you cannot expect the use of a different spelling somewhere else in the code to work. I keep relearning this fact the hard way.
My new technique is to cut and paste variable names in my code. It seems to be helping. I will say this. The examples in the book text are some nifty looking web pages. They are very clean and crisp. The exercises at the end of each chapter are decent but still somewhat lacking. Maybe I will have to sign up for a college course on JavaScript after all.