Create as many objects as you wish: You can initiate as many instances of the Myclass function as you want. If you create a widget class, you are not limited to creating only one in the page.
Share "this" across public methods: The "this" keyword is shared across all functions that are attached to the main class prototype. This means that the "this.arg" object is accessible through the public method "Myclass.method()". Public methods and the main class (function) itself can use the other public methods. To access them, use "this.method()".
One thing that I do too frequently is passing arguments to my initiated class. Usually, you have default parameters that are optional to change. The code features an elegant and simple solution to mix the passed arguments with an object (this.default) containing the default parameters. The code uses the jQuery extend function.
Be aware that this technique doesn't account for validation. So if you are looking to validate the passed parameters, you'd better try something else.