main.js

function server() {
    var ws_uri = "ws://localhost:8080/";
    var websocket = new WebSocket(ws_uri);
    websocket.onopen = function (event) {
        MessageAdd('<div class="message green">You have entered the chat room.</div>');
    };
    websocket.onclose = function (event) {
        MessageAdd('<div class="message blue">You have been disconnected.</div>');
    };
    websocket.onerror = function (event) {
        MessageAdd('<div class="message red">Connection to chat failed.</div>');
    };
    websocket.onmessage = function (event) {
        var data = JSON.parse(event.data);
        if (data.type == "message") {
            MessageAdd('<div class="message">' + data.username + ': ' + data.message + '</div>');
        }
    };
    document.getElementById("chat-form").addEventListener("submit", function (event) {
        event.preventDefault();
        var message_element = document.getElementsByTagName("input")[0];
        var message = message_element.value;
        if (message.toString().length) {
            var username = localStorage.getItem("username");
            var data = {
                type: "message",
                username: username,
                message: message
            };
            websocket.send(JSON.stringify(data));
            message_element.value = "";
        }
    }, false);
}
server();
function Username() {
    var username = window.prompt("Enter your username:", "");
    if (username.toString() == null) {
        var rastgele = Math.floor(Math.random() * 1000);
        localStorage.setItem("username", ("User " + rastgele));
    }
    else if (username.toString().length > 2) {
        localStorage.setItem("username", username);
    }
    else {
        alert("Your username must be at least two characters.");
        Username();
    }
}
Username();
function MessageAdd(message) {
    var chat_messages = document.getElementById("chat-messages");
    chat_messages.insertAdjacentHTML("beforeend", message);
    chat_messages.scrollTop = chat_messages.scrollHeight;
}
function debug() {
    var clienttext = document.getElementById("clienttext").innerHTML;
    console.log(clienttext);
    document.getElementById("clienttext").innerHTML = "";
}