Chained defer

gistfile1.js

// Execute fn for each element in arr, releasing to the UI
// thread (via underscore's _.defer) between each execution

_.chainedDefer = (function () {
    function next(arr, fn, scope) {
        if (!arr.length)
            return;
        
        fn.call(scope, arr.shift());

        _.chainedDefer(arr, fn, scope);
    }

    return function (arr, fn, scope) {
        _.defer(function () {
            next(arr, fn, scope);
        });
    };
})();