javascript: how to serialize form data to string without jquery or other libraries

var http_request = false;function makePOSTRequest(url, parameters) {  http_request = false;  if (window.XMLHttpRequest) { // Mozilla, Safari,...     http_request = new XMLHttpRequest();     if (http_request.overrideMimeType) {        // set type accordingly to anticipated content type        //http_request.overrideMimeType('text/xml');        http_request.overrideMimeType('text/html');     }  } else if (window.ActiveXObject) { // IE     try {        http_request = new ActiveXObject("Msxml2.XMLHTTP");     } catch (e) {        try {           http_request = new ActiveXObject("Microsoft.XMLHTTP");        } catch (e) {}     }  }  if (!http_request) {     alert('Cannot create XMLHTTP instance');     return false;  }  http_request.onreadystatechange = alertContents;  http_request.open('POST', url, true);  http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");  http_request.setRequestHeader("Content-length", parameters.length);  http_request.setRequestHeader("Connection", "close");  http_request.send(parameters);}function alertContents() {  if (http_request.readyState == 4) {     if (http_request.status == 200) {        //alert(http_request.responseText);        result = http_request.responseText;        document.getElementById('myspan').innerHTML = result;                 } else {        alert('There was a problem with the request.');     }  }}// call mefunction get(obj) {  var poststr = "mytextarea1=" + encodeURI( document.getElementById("mytextarea1").value ) +                "&mytextarea2=" + encodeURI( document.getElementById("mytextarea2").value );  makePOSTRequest('post.php', poststr);}

For those using npm and browserify, this here fits the bill: https://github.com/defunctzombie/form-serialize