The object instance on its own doesn't do much - the edit() method needs to be triggered to perform the actual editing. Typically a onclick handler is used to trigger editing of a value.
Ideally you should never instantiate wwEditable directly but rather use the static jQuery.makeEditable or jQuery.makeTableEditable methods.
var o = new wwEditable(element,callback,options)
callback
The function that is executed when focus is lost in the edited element.
options
The options match the properties of this class. If you want to preset any of the properties you can apply them to a map (ie. { updatedColor: "green", extraData: "myfield" } )