The seven rules of unobtrusive JavaScript: "I've found the following rules over the years developing, teaching and implementing JavaScript in an unobtrusive manner. They have specifically been the outline of a workshop on unobtrusive JavaScript for the Paris Web conference 2007 in Paris, France.
I hope that they help you understand a bit why it is a good idea to plan and execute your JavaScript in this way. It has helped me deliver products faster, with much higher quality and a lot easier maintenance."