Build a Website -- 2

A realtime collaboration application in which the div elements can be created, dragged, resized and edited in 'realtime' to all viewing the website; Something like, I create div of class X on the website and write "hello", at the same time on the other screen also, it would be written as hello in the div created very fast! Also a web application like MS paint in which we can draw using our mouse, change colors, here the drawing would also he realtime and everyone on the website will be able to see it in realtime.