Lesson 1: Communicating by using WebSocket CHAPTER 10 421
function writeOutput(message) {
var output = $("#divOutput");
output.html(output.html() + '<br />' + message);
}function checkSupported() {
if (window.WebSocket) {
writeOutput('WebSockets supported!');
return true;
}
else {
writeOutput('WebSockets NOT supported');
$('#btnSend').attr('disabled', 'disabled');
return false;
}
}function connect() {
webSocket = new WebSocket(wsUri);
webSocket.onopen = function (evt) { onOpen(evt) };
webSocket.onclose = function (evt) { onClose(evt) };
webSocket.onmessage = function (evt) { onMessage(evt) };
webSocket.onerror = function (evt) { onError(evt) };
}function keepAlive() {
var timeout = 15000;
if (webSocket.readyState == webSocket.OPEN) {
webSocket.send(‘’);
}
timerId = setTimeout(keepAlive, timeout);
}function cancelKeepAlive() {
if (timerId) {
cancelTimeout(timerId);
}
}function doSend() {
if (webSocket.readyState != webSocket.OPEN)
{
writeOutput("NOT OPEN: " + $('#txtMessage').val());
return;
}
writeOutput("SENT: " + $('#txtMessage').val());
webSocket.send($('#txtMessage').val());
}function onOpen(evt) {
writeOutput("CONNECTED");
keepAlive();
}