$.map(Array,Function)

$.map(Array array, Function fn) returns Array
Translate all items in an array to another array of items.

The translation function that is provided to this method is called for each item in the array and is passed one argument: The item to be translated.
The function can then return the translated value, 'null' (to remove the item), or an array of values - which will be flattened into the full array.

Example:

Maps the original array to a new one and adds 4 to each value.
$.map( [0,1,2], function(i){
return i + 4;
});

Result:
[4, 5, 6]