httpRequest, quick and easy

httpRequest.js

//
// httpRequest
// Make Cross Origin http requests for JSON data.
// The first path is url, the second is a callback, as a JSON object.
// If XHR CORS is not supported then JSONP is used. "&callback=" is appended to the request URL.
// @author Andrew Dodson

function httpRequest(url,callback){
	// IE10, FF, Chrome
	if('withCredentials' in new XMLHttpRequest()){
		var r = new XMLHttpRequest();
		// xhr.responseType = "json"; // is not supported in any of the vendors yet.
		r.onload = function(e){
			callback(r.responseText?JSON.parse(r.responseText):{error:{message:"Could not get resource"}});
		};
		r.open('GET', url);
		r.send( null );
	}
	else{
		// JSONP
		// Make the anonymous function. not anonymous
		var callback_name = 'jsonp_' + parseInt(Math.random()*1e10);
		window[callback_name] = callback;
		// find a place to insert the script tag
		var sibling = document.getElementsByTagName('script')[0];
		// Create the script tag
		var script = document.createElement('script');
		// Update the path with the callback name
		script.src = (url+"&callback="+callback_name);
		// Append
		sibling.parentNode.insertBefore(script,sibling);
	}
}