POST request by XMLHttpRequest

postRequest.js

function getCookie(key) {
    var cookies = document.cookie.split(';');
    for (var _i = 0, cookies_1 = cookies; _i < cookies_1.length; _i++) {
        var cookie = cookies_1[_i];
        // console.log(`cookie ${cookie}`);
        var cookiesArray = cookie.split('=');
        if (cookiesArray[0].trim() == key.trim()) {
            // console.log(`cookiesArray ${cookiesArray}`);
            let value = cookiesArray[1]; // (key[0],value[1])

            return value;
        }
    }
    return '';
}

function postRequest(url, json) {
    var res = null;
    var tryout = new XMLHttpRequest();
    tryout.open("GET", API_URL, false);
    tryout.withCredentials = true;
    tryout.setRequestHeader("x-csrf-token", "fetch");
    tryout.setRequestHeader("Accept", "application/json");
    tryout.setRequestHeader("Content-Type", "application/json; charset=utf-8");
    tryout.send(null);
    var csrftoken = getCookie('csrftoken');
    if (tryout.readyState === 4) {
        var csrfToken = tryout.getResponseHeader('x-csrf-token');

        tryout.open('POST', url, false);
        tryout.setRequestHeader("X-CSRFToken", csrftoken);
        tryout.setRequestHeader("Content-Type", "application/json; charset=utf-8");
        tryout.setRequestHeader("Accept", "application/json");

        tryout.send(json);

        if (tryout.readyState === 4) {
            res = JSON.parse(this.responseText);
            console.log('res:' + res);
        }
    }
}

var url = 'http://0.0.0.0:8000/';
var data = {'text': 'value'};
var json = JSON.stringify(data);
postRequest(url, json);