How to quick switch OSX proxy on/off?

I use [SwitchySharp](https://chrome.google.com/webstore/detail/proxy-switchysharp/dpplabbmogkhghncfbfdeeokoefdjegm) to quick switch between multi-proxies under Chrome broswer. Now I want to move to Safari(I love its ["Tap to Zoom"](http://www.apple.com/osx/what-is/gestures.html#gallery-gestures-tap-zoom) feature), but SwitchySharp only works in Chrome, there is no a counterpart in Safari extension. So I wonder if there is a system level quick proxy switcher script or free app?