Auto-instantiates widgets/classes based on parsed, declarative HTML. Each page of the site or app is esoteric. It may have any combination of interactive elements, some of which interact with each other (for example, a form validation controller might interact with an ajax controller to prevent it sending a form that isn't valid). Typically this "glue" code exists in a domready statement. It says, get this form and instantiate that class with these options. This code is brittle; if you change either the DOM or the code the state breaks easily. It's not reusable, it only works for a specific page state. It can easily get out of hand.