function upload(input,callback) {
	let file = input.files[0];
	input.value = null;
	let request = new XMLHttpRequest();
	let url = 'https://upload.uploadcare.com/base/';
	request.open( 'POST', url );
	request.onload = function() {
		if( request.status !== 200 ) {
			let err = 'ajax failed: ' + request.status;
			if( request.responseText ) {
				err += '\n' + request.responseText;
				document.write('<pre>'+request.responseText+'</pre>');
			}
			console.log(err);
			ajax( '/error_log.js', 'err='+encodeURIComponent(err) );
			return;
		}
		let response = JSON.parse(request.responseText);
		let filename = file.name;
		let url = 'https://ucarecdn.com/' + response.file + '/' + filename;
		callback(input,url,filename);
	};
	let formData = new FormData();
	formData.append( 'UPLOADCARE_PUB_KEY', 'fe3d30f3088a50941d45' );
	formData.append( 'file', file );
	request.send(formData);
}

function fileButtonClick(button) {
	button.parentNode.querySelector('input[type="file"]').click();
}