Drang n’ Drop in HTML 5 is supported by: IE9+, Firefox 3.6+, Safari 4+, Opera 11+ and Chrome 12+. But its not supported yet for touch devices like Touch Mobiles and Tablets.
Komodo Edit (Windows, Mac, Linux)
It has syntax coloring, folding, background syntax checking, auto-complete and calltips. It also includes libraries for autocompletion for jQuery, Ext JS, Ruby on rails and more.
I just recommend Komoodo Edit.