A simplified explanation of closures by Morris Johns: A closure is the local variables for a function - kept alive after the function has returned.
map() function, which is similar to Prototype's
this keyword is being used in the code. Snook offers workarounds to this by passing objects so that the context is correct, or using the
call() function to ensure the context is correct.
Dan Webb describes curried functions as a way of creating reusable callback functions for event handlers or Ajax requests, or anything that takes a function as an argument. By using closures, curried functions have a simple way of persisting data between calls. He also offers an elegant way of running a lots of methods on objects, with a simple map function written as a curried function.