Hier Funktioniert resourceCall nicht

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <link rel="stylesheet" href="Login_Register_GUI.css">

    </head>

    <body style="background-color:rgba(192,192,192,0.5);">
        <header><h1>Login/Register GUI</h1></header>
        <nav class="Tabs">
            <button class="tabButton" onclick="openTab('LoginTab')">Login</button>
            <button class="tabButton" onclick="openTab('RegisterTab')">Register</button>


        </nav>
        <div id="LoginTab" class="tab">

           <!-- <form class="login-form"> -->
                    <!-- Text input-->
                <div class="form-group">
                    <label class="label-group" for="loginusername">Username*</label>

                        <input id="loginusername" placeholder="Type in Username here" class="inputTb" required type="text">

                </div>
                    <!-- Password input-->
                <div class="form-group">
                    <label class="label-group" for="loginpassword">Password*</label>

                        <input id="loginpassword" placeholder="Type in Password here" class="inputTb" required type="password">

                </div>
                    <!--Checkbox (inline) -->
                        <div class="showPwBox">
                            <label class="checkbox-inline" for="showPwBox">
                                <input name="showPwBox" id="showPwBox" value="showPw" type="checkbox">
                                <span class="label-group">Show Password</span>
                            </label>
                        </div>
                    <!-- Buttons -->

                        <!--<label class="col-md-4 control-label" for="leaveBtn"></label>-->
                        <div class="button-group">
                            <button id="loginbtn" type="button"  onclick="loginMyUser()" name="loginbtn" class="btnGroup">Login</button>
                            <button id="recoverBtn" type="button" name="recoverBtn" class="btnGroup">Recover Password</button>
                            <button id="leaveBtn" type="button" name="leaveBtn" onclick="onLeave()" class="btnGroup">Leave</button>
                        </div>


            <!--</form>-->
        </div>

        <div id="RegisterTab" class="tab" style="display:none">
            <!--<form id="reg-form">-->

                <!--- Username Label and Inputfield-->
                <div class="fb-text form-group field-regusername">
                <label for="regusername" class="label-group">Username<span class="fb-required">*</span></label>
                <input placeholder="Type in Username here" class="inputTb" id="regusername" required type="text">
                </div>
                <!-- Password Label and Inputfield-->
                <div class="fb-text form-group field-regpassword">
                <label for="regpassword" class="label-group">Password<span class="fb-required">*</span></label>
                <input placeholder="Type in Password here" class="inputTb" id="regpassword" required type="password">
                    </div>
                <!--Validate Password Label and Inputfield-->
                <div class="fb-text form-group field-regpwvalid">
                <label for="regpwvalid" class="label-group">Validate Password<span class="fb-required">*</span></label>
                <input placeholder="Type in Password here again" class="inputTb" id="regpwvalid" required type="password">
                    </div>
                <!--Email Label and Inputfield-->
                <div class="fb-text form-group field-regemail"><label for="regemail" class="label-group">E-Mail</label>
                <input placeholder="Type in your E-Mail here (optional)" class="inputTb" name="regemail" id="regemail" title="(optional) If you don't fill in your E-Mail you won't be able to recover your Password if you lose it!" type="email">
                    </div>
                <!--Buttons-->
                <div class="regBtn-group">
                    <button type="button" class="regBtn" onclick="registerMyUser()" name="regbtn"  id="regbtn">Register</button>
                    <button type="button" class="regBtn" onclick="onLeave()" name="regleave" id="regleave">Leave</button>
                </div>
                </div>
           <!-- </form>-->


        <script >
            function openTab(tabName) {
                var i;
                var x = document.getElementsByClassName("tab");
                for (i = 0; i < x.length; i++) {
                    x[i].style.display = "none";
                }
                document.getElementById(tabName).style.display = "block";
            }

            document.getElementById('showPwBox').onclick = function () {
                if (this.checked) {
                    document.getElementById('loginpassword').type = "text";
                }
                else {
                    document.getElementById('loginpassword').type = "password";
                }
            }
            function loginMyUser () {

                var username = document.getElementById("loginusername").value;
                var password = document.getElementById("loginpassword").value;
                if (username == "") {
                    alert("Fill out Username");
                }
                else if (password == "") {
                    alert("Fill out Password");
                }
                else {

                    ResourceCall("onLoginUser", username, password);
                    alert("Hallo login");
                }
            };

            function registerMyUser() {
                //alert("Servus");

                var username = document.getElementById("regusername").value;
                var password = document.getElementById("regpassword").value;
                var validPw = document.getElementById("regpwvalid").value;
                var email = document.getElementById("regemail").value;
                if (username == "") {
                    alert("Fill out Username");
                }
               else if (password == "") {
                    alert("Fill out Password");
                }
                else if (validPw !== password) {
                    alert("Password incorrect!");
                }
                else {


                    ResourceCall("onRegisterUser", username, password, email);

                    alert("Hallo " + username);
                }
            };


            function onLeave() { ResourceCall("DisconnectUser"); }


        </script>

    </body>
</html>