ParsingHTTPResponse.js

// Issue an HTTP GET request for the contents of the specified URL. // When the response arrives, pass it to the callback function as a // parsed XML Document object, a JSON-parsed object, or a string. function get(url, callback) { var request = new XMLHttpRequest(); // Create new request request.open("GET", url); // Specify URL to fetch request.onreadystatechange = function() { // Define event listener // If the request is compete and was successful if (request.readyState === 4 && request.status === 200) { // Get the type of the response var type = request.getResponseHeader("Content-Type"); // Check type so we don't get HTML documents in the future if (type.indexOf("xml") !== -1 && request.responseXML) callback(request.responseXML); // Document response else if (type === "application/json") callback(JSON.parse(request.responseText)); // JSON response else callback(request.responseText); // String response } }; request.send(null); // Send the request now }