more robust maybe

client.js

 	function post(url, cb) {
 		var xhr = new XMLHttpRequest();
 
+		let timeout = setTimeout(function() {
+			console.log("Timed out, aborting.");
+			xhr.abort();
+		}, 3000);
+
 		xhr.addEventListener("load", function() {
+			clearTimeout(timeout);
 			try {
 				var obj = JSON.parse(xhr.responseText);
 			} catch (err) {
 		});
 
 		xhr.addEventListener("error", function(err) {
+			clearTimeout(timeout);
 			cb(err);
 		});
 		xhr.addEventListener("abort", function(err) {
-			console.log("Aborted.");
+			clearTimeout(timeout);
 			cb(err);
 		});
 

test.js

 
 http.createServer(function(req, res) {
 	if (req.url == "/") {
+		res.writeHead(200, {
+			"Content-Type": "text/html",
+		});
 		res.end(html);
 	} else if (req.url == "/client.js") {
 		fs.createReadStream("client.js")