Docs
Without the documentation of a framework, or project, it becomes almost useless. It's a pain the butt to keep the documentation up-to-date and very thorough for new comers and advance users, but its the key to open source.
Lets begin with the basics.
GOOPJS extends elements with 5 types of methods: basic, styles, events, dimensions, and effects.
If you want to extend an element by one of GOOPJS's methods, you would pass the element(s) as the first parameter to the function GOOP.extend() like so:
GOOP.extend(document.getElementById("theid"));
By default, it will extend the element(s) with all of GOOPJS's methods. If you want to be more precise on what methods to use on the element(s), you may use the second parameter like so:
// pass an array of what methods to attach to the element
GOOP.extend(document.getElementById("id1"),["styles","events"]);
// if you pass an empty array, only the "basic" will be applied
GOOP.extend(document.getElementById("id2"),[]);
// if you say "false", no methods will be applied
GOOP.extend(document.getElementsByTagName("DIV"),false);
There are two functions that are similar to document.getElementById() and document.getElementsByTagName(). They are $() and $$(). $() accepts either a string or an element to be extend through GOOPJS. The $$() accepts a string and will look through the document.body to find the element(s) and return them as an Array extended by GOOPJS (if any found, null otherwise).
Hopefully I didn't overwhelm you... its really basic and easy to understand once you try it out. No more explaining, the rest is up to you. Click through the doc pages and discover.