function checkNickname() {
    let nickname = document.getElementById("nickname").value;
    let resp;
    fetch("http://edi.iem.pw.edu.pl/chaberb/register/check/" + nickname, {
        mode: "no-cors",
        headers: {
            "Content-Type": "application/json"
        },
    })
        .then(function (response) {
            resp = response
        })
        .catch(function (response) {
            console.log(response)
        });

    if ( resp ) {
        document.getElementById("nicknameCheckResponse").innerHTML = "Nickname too awesome and is already taken"
    }
}

function sendForm() {
    fetch('http://edi.iem.pw.edu.pl/chaberb/register/user/', {
            method: 'POST',
            body: document.getElementById("form")
        }).then(function (response) {
            console.log(response)
        })
        .catch(function (response) {
            console.log(response)
        })
}