function login() {
    let nicknameF = document.getElementById("nickname"); // fetch fields
    let pwF = document.getElementById("password");
    let nickname = nicknameF.value; // extract values
    let pw = pwF.value;

    let loginReq = {
        action: "login",
        nickname: nickname,
        password: pw
    };

    request(loginReq).then(resp => {
        if (resp === "OK") {
            location.href = "main.php"
        }
    });
}

function open_in_content_frame(url) {
    document.getElementById("content_frame").src = url;
}

var USERDATA = {};
function load_userdata() {
    let req = {action: "get_user_info"};
    request(req).then(resp => {
        USERDATA = JSON.parse(resp);
    });
}

load_userdata();

function create_table_cell(content, styleClass = "") {
    if (content.trim() === "") {
        content = "<i>(üres)</i>";
    }
    let td = document.createElement("td");
    td.innerHTML = content;
    if (styleClass !== "") {
        td.classList.add(styleClass);
    }
    return td;
}

// ---------------

function highlight_row(nickname) {
    let hl_on = document.getElementById("user_chk_" + nickname).checked;
    let row = document.getElementById("row_" + nickname);
    row.setAttribute("highlight", hl_on ? "true" : "false");
}