Simple, Plain, Customizable JS Dialogs.

Frustrated by the lack of a simple, customizable JS dialog, I decided to create a mini library that captures the simplicity of the 3 classic JS dialogs: alert, confirm, prompt, but allows for needed custom features like styling, button labels, and html5 placeholders for inputs. Seeking feedback on any potential issues, code architecture and style, and general usefulness. Before you chime in about jQuery UI or some other framework/library that has this included, think first about projects that don't require such a heavily scripted or styled component and would benefit from a straightforward, easy to customize solution.