Quick prototyping tool to consume REST API results on the web

I am interested in writing an HTML5 application that consumes REST APIs. I am wondering if there are interesting tools that can help me prototype a UI really quickly?

For example is it easy to consume REST api's in jQuery? are there other tools/libraires that make it easier.

Something like dashcode for Li开发者_如何学运维nux or windows

For the UI prototype there are tools like

1. Balsamiq http://www.balsamiq.com/
2. JustinMindPrototyper http://www.justinmind.com/

Otherwise some great ideas come from Ryan Singer's (37Signals UI guy) talk on "Design and Prototyping" http://feltpresence.com/ The interesting point is that some of the UI prototype tools create a high-fidelity version, when in fact if you are trying to design and get an interative/agile process going then a low-fidelity prototype works best.