function uploadfile(file, url, success, progress){
	const ajax = new XMLHttpRequest();
	const formData = new FormData();

	if (el instanceof Element) file=file.files[0];

	formData.append('file', file);

	if (typeof progress=='function') {
		ajax.upload.addEventListener(
			'progress',
			function ProgressHandler(event){
				const p = Math.floor((event.loaded / event.total) * 100);
				progress(`${p}%`);
			}
		);
	}
	if (success) ajax.addEventListener('load', success, false);
	ajax.open('POST', url, true);
	ajax.send(formData);
}