A lame little JSONP implementation

request.js

var request = function(options) {
    var aborted = false,
        abort = function() {
            aborted = true;
        };

    switch (options.type) {
        case "jsonp":
            // a very simplistic JSON-P implementation
            var script = document.createElement("script"),
                callback = options.jsonpCallbackName || "callback";
            script.src = options.url;
            script.async = true;
            script.className = "eddy-jsonp";
            script.onerror = function() {
                cleanup();
                if (options.error) options.error.apply(null, arguments);
            };

            function cleanup() {
                if (script.parentNode) script.parentNode.removeChild(script);
                if (callback in window) delete window[callback];
            }

            abort = function() {
                aborted = true;
                cleanup();
            };

            window[callback] = function() {
                cleanup();
                if (!aborted) {
                    if (options.success) options.success.apply(null, arguments);
                }
            };

            document.getElementsByTagName("script")[0].parentNode.appendChild(script);
            break;

        default:
            throw "Unsupported request type: " + options.type;
    }
    return {
        abort: abort
    };
};