formData.js

function appendAndSendImageHW() {
	var allFiles = document.querySelector('input').files;
	for (var i = 0; i < allFiles.length; i++) {
		var file = allFiles[i];
		var newImg = new Image();
		newImg.onload = function() {
			console.log(newImg.height, newImg.width);
			file["height"] = newImg.height;
			file["width"] = newImg.width;
		}
		newImg.src = window.URL.createObjectURL(allFiles[i]);
	}
	var formElement = document.querySelector("form");
	var formData = new FormData(formElement);
	var request = new XMLHttpRequest();
	request.open("POST", "/api/upload");
	formData.append("dummyParamater", "dummyParamater");
	request.send(formData);	
}