kllaudyo/upload.html

## upload.html
<html>
  <body>
    <input type="file" name="picture" id="picture" />
    <pre></pre>
  </body>
  <script>
    window.onload = function(){

      const getRequestHeaders = () => new Headers({
        'Accept': 'application/json'
      });

      const upload = data =>
            //Imaginando um retorno do tipo: json_encode($_FILES);
	    fetch('/api', { method:'POST', headers:getRequestHeaders(), body:data })
	      .then( response => response.json())
	      .then( response => document.querySelector("pre").innerHTML = JSON.stringify(response))
	      .catch( error => document.querySelector("pre").innerHTML = JSON.stringify(error))
      ;

      const multipart = arguments => {
	//Ao utilizar FormData não utilizar o header Content-Type
        const data = new FormData();
	Object.keys(arguments).map(key => data.set(key, arguments[key]));
        return data;
      };

      const onSelectFile = e => {
        if(e.target.files)
          upload(multipart({"file":e.target.files[0]}));
        else
          document.querySelector("pre").innerHTML = "Impossível anexar arquivo";
      };

      document.querySelector("#picture").onchange = onSelectFile
    };
  </script>
</html>
	<html>
	<body>
	<input type="file" name="picture" id="picture" />
	<pre></pre>
	</body>
	<script>
	window.onload = function(){

	const getRequestHeaders = () => new Headers({
	'Accept': 'application/json'
	});

	const upload = data =>
	//Imaginando um retorno do tipo: json_encode($_FILES);
	fetch('/api', { method:'POST', headers:getRequestHeaders(), body:data })
	.then( response => response.json())
	.then( response => document.querySelector("pre").innerHTML = JSON.stringify(response))
	.catch( error => document.querySelector("pre").innerHTML = JSON.stringify(error))
	;

	const multipart = arguments => {
	//Ao utilizar FormData não utilizar o header Content-Type
	const data = new FormData();
	Object.keys(arguments).map(key => data.set(key, arguments[key]));
	return data;
	};

	const onSelectFile = e => {
	if(e.target.files)
	upload(multipart({"file":e.target.files[0]}));
	else
	document.querySelector("pre").innerHTML = "Impossível anexar arquivo";
	};

	document.querySelector("#picture").onchange = onSelectFile
	};
	</script>
	</html>