Web design IDE like FlexBuilder?

I have been working with Adobe Flex for the last 2 years and I would like to build a html interface for my next project. I am missing the ease of use of flexbuilder and the speed with which I could translate the design into working code. Are there any such tools for any of the JS toolkits? Visual design is not very important, but having a clean event handling mechanism, auto complete for code and split between layout and event handlers are.