Create an Auphonic production. Then upload a file to that production.

auphonic_file_upload.js

// Create the XHR object
function createCORSRequest(method, url) {
	var xhr = new XMLHttpRequest();
	if ("withCredentials" in xhr) {
		xhr.open(method, url, true); // XHR for Chrome/Firefox/Opera/Safari
	} else if (typeof XDomainRequest != "undefined") {
		xhr = new XDomainRequest(); // XDomainRequest for IE
		xhr.open(method, url);
	} else {
		xhr = null; // CORS not supported
	}
	return xhr;
}

function get_token() {
	return 'XXXXXXX'; // your token
}

var xhr = new createCORSRequest("POST", "https://auphonic.com/api/productions.json");
xhr.setRequestHeader("Content-type","application/json");
xhr.setRequestHeader("Authorization","Bearer " + get_token());
xhr.onload = function(e) {
	var response = JSON.parse(e.target.response),
		data = response.data,
		production_uuid = data.uuid,
		file = document.querySelector('#auphonic_local_upload_url').files[0];

	console.log("Production: created");

	if (file) {
		console.log("File Upload: started");

		var url = 'https://auphonic.com/api/production/{uuid}/upload.json'.replace('{uuid}', production_uuid),
			xhr2 = new createCORSRequest("POST", url),
			formData = new FormData();

	 	xhr2.setRequestHeader("Authorization","Bearer " + get_token());
		xhr2.upload.addEventListener("progress", function(e) { console.log((e.loaded / e.total) * 100) }, false);
		xhr2.onload = function(e) {
			console.log("File Upload: Done");
		};

		formData.append('input_file', file);
		xhr2.send(formData);
	}
};
xhr.send(JSON.stringify({"metadata":{"title":"test"}}));