A little exercise with the following task:

Create a single-page JavaScript app that does the following:

- With a button the user can add 30x30px divs files with a random color in a random position on the screen.
- The user can drag around these boxes on the page, resize and delete them. Make up your own UI for that - it doesn't need to look nice.
- Don't use any JS libraries.
- Support Chrome, Safari, FF and IE9

My comments:

- I made the UI with mouse input in mind as I thought of that when I read about the browsers that should be supported. Later I added support for iOS but the UI is not optimized for touch input (I have ideas, though).