Pure JavaScript Send POST Data Without a Form

The Fetch API is intended to make GET requests easy, but it is able to POST as well.

let data = {element: "barium"};

fetch("/post/data/here", {
  method: "POST",
  headers: {'Content-Type': 'application/json'}, 
  body: JSON.stringify(data)
}).then(res => {
  console.log("Request complete! response:", res);
});

If you are as lazy as me (or just prefer a shortcut/helper):

window.post = function(url, data) {
  return fetch(url, {method: "POST", headers: {'Content-Type': 'application/json'}, body: JSON.stringify(data)});
}

// ...

post("post/data/here", {element: "osmium"});

You can use XMLHttpRequest, fetch API, ...

If you want to use XMLHttpRequest you can do the following

var xhr = new XMLHttpRequest();
xhr.open("POST", url, true);
xhr.setRequestHeader('Content-Type', 'application/json');
xhr.send(JSON.stringify({
    name: "Deska",
    email: "deska@gmail.com",
    phone: "342234553"
 }));
xhr.onload = function() {
    var data = JSON.parse(this.responseText);
    console.log(data);
};

Or if you want to use fetch API

fetch(url, {
    method:"POST",
    body: JSON.stringify({
        name: "Deska",
        email: "deska@gmail.com",
        phone: "342234553"
        })
    }).then(result => {
        // do something with the result
        console.log("Completed with result:", result);
    }).catch(err => {
        // if any error occured, then catch it here
        console.error(err);
    });

There is an easy method to wrap your data and send it to server as if you were sending an HTML form using POST. you can do that using FormData object as following:

data = new FormData()
data.set('Foo',1)
data.set('Bar','boo')

let request = new XMLHttpRequest();
request.open("POST", 'some_url/', true);
request.send(data)

now you can handle the data on the server-side just like the way you deal with reugular HTML Forms.

Additional Info

It is advised that you must not set Content-Type header when sending FormData since the browser will take care of that.

Did you know that JavaScript has it's built-in methods and libs to create forms and submit them?

I am seeing a lot of replies here all asking to use a 3rd party library which I think is an overkill.

I would do the following in pure Javascript:

<script>
function launchMyForm()
{
   var myForm = document.createElement("FORM");
   myForm.setAttribute("id","TestForm");
   document.body.appendChild(myForm);

// this will create a new FORM which is mapped to the Java Object of myForm, with an id of TestForm. Equivalent to: <form id="TestForm"></form>

   var myInput = document.createElement("INPUT");
   myInput.setAttribute("id","MyInput");
   myInput.setAttribute("type","text");
   myInput.setAttribute("value","Heider");
   document.getElementById("TestForm").appendChild(myInput);
   
// To submit the form: 
   myForm.method = "POST";
   myForm.action = "whatever.aspx";  // or "response.php" 
   myForm.submit();

// This will create an INPUT equivalent to: <INPUT id="MyInput" type="text" value="Heider" /> and then assign it to be inside the TestForm tags. 
}
</script>

This way (A) you don't need to rely on 3rd parties to do the job. (B) It's all built-in to all browsers, (C) faster, (D) it works, feel free to try it out.

I hope this helps.

H

navigator.sendBeacon()

If you simply need to POST data and do not require a response from the server, the shortest solution would be to use navigator.sendBeacon():

const data = JSON.stringify({
  example_1: 123,
  example_2: 'Hello, world!',
});

navigator.sendBeacon('example.php', data);

The most popular answers here do not show how to get data back from the POST. Also, the popular "fetch" solutions do not work in the latest version of Chrome when sending data to the latest version of NodeJS unless you pass headers and also unwrap the response.json() promise. Also, the popular answers do not use async/await.

Here is the cleanest and most complete solution I could come up with that works.

async function postJsonData(jsonObject) {
    const response = await fetch("/echo", {
        method: "POST",
        headers: {'Content-Type': 'application/json'},
        body: JSON.stringify(jsonObject)
    });
    
    const actualResponse = await response.json();
}

Here is a nice function you (or anyone else) could use in their code:

function post(url, data) {
    return new Promise((res, rej) => {
        let stringified = "";
        for (const [key, value] of Object.entries(data))
            stringified += `${stringified != '' ? '&' : ''}${key}=${value}`

        const xhr = new XMLHttpRequest();
        xhr.onreadystatechange = () => {
            if (xhr.readyState == 4)
                if (xhr.status == 200)
                    res(xhr.responseText)
                else
                    rej({ code: xhr.status, text: xhr.responseText })
        }
        xhr.open("POST", url, true);
        xhr.setRequestHeader('Content-Type', 'application/json');
        xhr.send(stringified);
    })
}

const data = { username: 'example' };

fetch('https://example.com/profile', {
  method: 'POST', // or 'PUT'
  headers: {
 '           Content-Type': 'application/json',
           },
  body: JSON.stringify(data),
})
  .then(response => response.json())
  .then(data => {
      console.log('Success:', data);
     })
 .catch((error) => {
         console.error('Error:', error);
   });

You can also use this: https://github.com/floscodes/JS/blob/master/Requests.js

You can easily send a http-Request. Just use:

HttpRequest("https://example.com", method="post", data="yourkey=yourdata");

That's it! It should even work if the site is CSRF-protected.

Or just send a GET-Request by using

HttpRequest("https://example.com", method="get");

use this func of jbezz library

var makeHttpObject = function () {
  try {return new XMLHttpRequest();}
  catch (error) {}
  try {return new ActiveXObject("Msxml2.XMLHTTP");}
  catch (error) {}
  try {return new ActiveXObject("Microsoft.XMLHTTP");}
  catch (error) {}
  throw new Error("Could not create HTTP request object.");
}
function SendData(data){
    let type = (data.type ? data.type : "GET")
    let DataS = data.data;
    let url = data.url;
    let func = (data.success ? data.success : function(){})
    let funcE =(data.error ? data.error : function(){})
    let a_syne = (data.asyne ? data.asyne : false); 
    let u = null;
    try{u = new URLSearchParams(DataS).toString();}catch(e){u = Object.keys(DataS).map(function(k) {return encodeURIComponent(k) + '=' + encodeURIComponent(DataS[k])}).join('&')}
    if(type == "GET"){url +="?"+u}
    const xhttp =  makeHttpObject();
    xhttp.onload = function(){func(this.responseText)}
    xmlHttp.onreadystatechange = function() {if (xmlHttp.readyState == 4) 
    {if(xmlHttp.status !== 200){funcE(xmlHttp.statusText)}}}
    xhttp.open(type,url,a_syne);
    xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    xhttp.send(u);
}

use this to run :

SendData({
    url:"YOUR_URL",
    asyne:true,
    type:"POST", // or GET
    data:{
        username:"ali",
        password:"mypass" // Your Data
    },
    success:function(Result){
        console.log(Result)
    },
    error:function(e){
        console.log("We Have Some Error")
    }
});

Or

download jbezz and add to your page.

download link : github.com

use :

$$.api({
        url:"YOUR_URL",
        asyne:true,
        type:"POST", // or GET
        data:{
            username:"ali",
            password:"mypass" // Your Data
        },
        success:function(Result){
            console.log(Result)
        },
        error:function(e){
            console.log("We Have Some Error")
        }
    });