polling

I'm trying to implement a WebSocket with a fallback to polling. If the WebSocket connection succeeds, readyState becomes 1, but if it fails, readyState is 3, and I should begin polling. I tried something like this: var socket = new WebSocket(url); socket.onmessage = onmsg; while (socket.readyState == 0) { } if (socket.readyState != 1) { // fall back to polling setInterval(poll, interval); } I was expecting socket.readyState to update asynchronously, and allow me to read it immediately. However, when I run this, my browser freezes (I left it open for about half a minute before giving up). I

I'm a novice-to-intermediate JavaScript/jQuery programmer, so concrete/executable examples would be very much appreciated. My project requires using AJAX to poll a URL that returns JSON containing either content to be added to the DOM, or a message { "status" : "pending" } that indicates that the backend is still working on generating a JSON response with the content. The idea is that the first request to the URL triggers the backend to start building a JSON response (which is then cached), and subsequent calls check to see if this JSON is ready (in which case it's provided). In my script, I

How has Google implemented their push notification feature? Does it work through polling done by a service running in the background or in a different way? Tal Kanel From what I've heard during an Android developers conference in Israel: There is simply a TCP socket waiting in accept mode on a cloud Google server. The TCP connection had been initiated by the Google Play application. That's why Google Play must be installed on the device for making Google Cloud Messaging (GCM) (formerly Android Cloud to Device Messaging Service - C2DM ) work. When this TCP client socket receives some message,

What is best practise for polling server with JavaScript for application that needs to refresh data very rapidly? I'm using jQuery for front-end and Java Spring Framework for backend. Example of refreshed data could be list of items that are getting updated very rapidly (every 1 second). Daniel Vassallo You may want to use jQuery's Ajax functions to poll the server every second or so. Then the server can respond with instructions to the browser in near real-time. You can also consider long polling instead of the above, to reduce the latency without increasing the frequency of the polls.