An external resource request function for modern (i.e. BlobBuilder-supporting) browsers and FF5.

README.md

API

XMLHttpRequest request({
    String url
    // type can be buffer, blob, text, or document
    optional String type = "buffer"
    optional String|ArrayBuffer|Blob|FormData|Document data
    optional Function callback(type data)
    optional Function onerror()
})

Note: In order to use the document type with text/html requests, make sure to include my DOMParser HTML extension.

request.js

var request = (function(view) {
"use strict";
var
	  XHR = XMLHttpRequest
	, BB = view.BlobBuilder || view.WebKitBlobBuilder || view.MozBlobBuilder
	, DOMURL = view.URL || view.webkitURL || view
	, dom_parser = new DOMParser
	, resp_type_supported = "responseType" in new XHR
	, buff_supported
	, blob_supported
	, text_supported
	, doc_supported
	, request = function(opts) {
		var
			  url = opts.url
			, data = "data" in opts ? opts.data : null
			// type can be buffer, blob, text, or document
			// note that the blob type is unsupported in FF5 without BlobBuilder.js
			, type = opts.type || "buffer"
			, blob_req = type === "blob"
			, buff_req = type === "buffer"
			, binary_req = buff_req || blob_req
			, doc_req = type === "document"
			, text_req = type === "text"
			, resp_type = type
			, callback = opts.callback
			, onerror = opts.onerror
			, req = new XHR
		;
		req.open(data === null ? "GET" : "POST", url, true);
		if (buff_req || blob_req && !blob_supported) {
			resp_type = "arraybuffer"
		}
		if (doc_req && !doc_supported) {
			resp_type = "";
		}
		req.responseType = resp_type;
		if (callback) {
			req.addEventListener("load", function() {
				var
					  type = req.getResponseHeader("Content-Type")
					, data = req.response
					, text, bb
				;
				if (binary_req) {
					data = data || req.mozResponseArrayBuffer;
					if (blob_req && !blob_supported) {
						bb = new BB;
						bb.append(data);
						data = bb.getBlob(type);
					}
				} else if (text_req) {
					data = data || req.responseText;
				} else if (doc_req) {
					if (!doc_supported) {
						data =
							   req.responseXML
							|| dom_parser.parseFromString(req.responseText, type)
						;
					}
				}
				callback.call(req, data);
			}, false);
		}
		if (onerror) {
			req.addEventListener("error", function() {
				onerror.apply(req, arguments);
			}, false);
		}
		req.send(data);
		return req;
	}
	, test_object_url
	, test_resp_type = function(type) {
		var test_req = new XHR;
		test_req.open("GET", test_object_url, false);
		test_req.responseType = type;
		test_req.send();
		return test_req.response !== null;
	}
;
if (resp_type_supported && BB) {
	test_object_url = DOMURL.createObjectURL((new BB).getBlob("text/html"));
	buff_supported = test_resp_type("arraybuffer")
	blob_supported = test_resp_type("blob");
	text_supported = test_resp_type("text")
	doc_supported = test_resp_type("document");
	DOMURL.revokeObjectURL(test_object_url);
}
return request;
}(self));