POST data in JSON format
JavascriptJsonPostXmlhttprequestJavascript Problem Overview
I have some data that I need to convert to JSON format and then POST it with a JavaScript function.
<body onload="javascript:document.myform.submit()">
<form action="https://www.test.net/Services/RegistrationService.svc/InviteNewContact" method="post" name="myform">
<input name="firstName" value="harry" />
<input name="lastName" value="tester" />
<input name="toEmail" value="[email protected]" />
</form>
</body>
This is the way the post looks now. I need it submit the values in JSON format and do the POST with JavaScript.
Javascript Solutions
Solution 1 - Javascript
Not sure if you want jQuery.
var form;
form.onsubmit = function (e) {
// stop the regular form submission
e.preventDefault();
// collect the form data while iterating over the inputs
var data = {};
for (var i = 0, ii = form.length; i < ii; ++i) {
var input = form[i];
if (input.name) {
data[input.name] = input.value;
}
}
// construct an HTTP request
var xhr = new XMLHttpRequest();
xhr.open(form.method, form.action, true);
xhr.setRequestHeader('Content-Type', 'application/json; charset=UTF-8');
// send the collected data as JSON
xhr.send(JSON.stringify(data));
xhr.onloadend = function () {
// done
};
};
Solution 2 - Javascript
Here is an example using jQuery...
<head>
<title>Test</title>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
<script type="text/javascript" src="http://www.json.org/json2.js"></script>
<script type="text/javascript">
$(function() {
var frm = $(document.myform);
var dat = JSON.stringify(frm.serializeArray());
alert("I am about to POST this:\n\n" + dat);
$.post(
frm.attr("action"),
dat,
function(data) {
alert("Response: " + data);
}
);
});
</script>
</head>
The jQuery serializeArray function creates a Javascript object with the form values. Then you can use JSON.stringify to convert that into a string, if needed. And you can remove your body onload, too.
Solution 3 - Javascript
Using the new FormData object (and other ES6 stuff), you can do this to turn your entire form into JSON:
let data = {};
let formdata = new FormData(theform);
for (let tuple of formdata.entries()) data[tuple[0]] = tuple[1];
and then just xhr.send(JSON.stringify(data)); like in Jan's original answer.