Understand JavaScript syntax and structures.

• Create scripts that are easy to understand and maintain.
• Write scripts that do not interfere with other JavaScripts.
• Write scripts that make web sites easier to use without blocking out non-JavaScript users.
• Write scripts that are independent of the browser or user agent trying to understand
them—which means that in some years they will still be usable and won’t rely on obsolete
technology.
• Enhance a web site with JavaScript and allow developers without any scripting knowledge
to change the look and feel.
• Enhance a web document with JavaScript and allow HTML developers to use your functionality
by simply adding a CSS class to an element.
• Use progressive enhancement to make a web document nicer only when and if the user
agent allows for it.
• Use Ajax to bridge the gap between back end and client side, thus creating sites that are
easier to maintain and appear much slicker to the user.
• Use JavaScript as part of a web methodology that enables you to maintain it independently
without interfering with the other development streams.

read again and again dude