Using this circular jQuery plugin you can easily create beautiful circular switches similar to volume controls. The plugin’s called jQuery Knob and works by transforming any given input field according to the values defined. You can easily drag and drop to change values.
You can also use it to define mix or max values, select a default value on initial load, change the color of it or put it in read only mode. The circular jQuery plugin supports touch, mousewheel and keyboard events and its released under GPL and MIT license so you are free to customize it as you want.