Building UI Forms from scratch

My hands are itching to create a bonafide Canvas UI Form ala(Winforms) from scratch entirely written in JavaScript that will run cross browser on desktop or probably on any device using modern browser. A form that can be Activate, DeActivate, Minimize, Maximize, Restore, Close and Resize and have GUI children.

Ok, I know it's an incredible amount of work and a huge undertaking, but I need it for my 2D tile editor running in the browser; for educational purposes it will surely fun coding it : - D