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Creating a real-time chat with php and javascript

My goal is to create a real-time chat similar to the Facebook chat, from scratch. I want to store all the messages on a database table (MySQL) and every time a new message is sent by a user, if the receiver is connected then a request will be sent to the receiver's browser and the message will appear on the chat window.
I don't want to have the client to check if a new message for the user was sent, but I want the server to send the request to the client's browser.
I know that this can be achieved using the Comet technique (I saw this stackoverflow question) but I am not able to find a good guide on how to implement this for this certain problem.
I want to use php and javascript and as less extra software or frameworks as possible.
I use WAMPServer and I have Windows.
If you know a good guide or tutorial or can provide any guidelines on how I could achieve what I want, it would be very helpful.

Try use for this CppComet open source comet server. There have api for php and other languages.
And viwe this chat example or this

You can also use Node.JS with PHP. Creating a Real-Time Chat App with PHP and Node.js

I have already developed an application which is not completely Real-time messaging system, but it works like realtime. Built using without any external new frameworks/API, just used known and familiar skills to develop this using: Ajax jquery, PHP, Mysql, Javascript.
Logic used is:
All messages will be stored in database,
When you load page all messages will be loaded from database.
When you get new messages after reloading, the new messages has to be
loaded/displayed without reloading whole page again right? This is done
using javaScript and ajax jquery. I have set time out for EVERY 0.5 seconds
to reload only new messages and display them.
In my code, At first when the page loads all messages will be loaded in div
tags each, Later whenever new message gets into db it will displayed into new
div tags. its Simple and works without any external API.
To refresh new messages and throw them in to div tags .load() from ajax jquery is used,
to refresh every 0.5secs Javascript is used to set timeout.

I don't know what your exact question is but Websockets is the answer!
https://github.com/crossbario/autobahn-js
https://github.com/voryx/Thruway
(FYI, when you see WAMP in the context of websockets they're talking about something that's not windows/apache/mysql/php)

Unfortunately you can't make a real time application with PHP it self you can use a framework like Laravel in PHP and use packages like laravel-websockets and create a realtime application. laravel-websockets is really useful for creating a realtime application. laravel and the laravel websokcets with any front end you can do this
http://beyondco.de/docs/laravel-websockets
https://laravel.com/docs/
You can easy create anything with it just try to understand the fundamental concept of websokcets .

Pubnub: Background Processes for an Auction App Development

Hello I am developing an auction app like tophatter.com. I want to implement an application that has background process in it. I want this process to run forever until I stop it
http://eoction.com thatss our current site. The problem on our site when we refresh the page the auction also restart. We need something like a continuous process like tophatter.com if you refresh the page it will load the updated auction process.
I found this great service called pubnub. I am thinking we need a background process for this? This will process the auction on the pubnub blocks and then when we visit the site we will just need to query on its updated process?
Does pubnub support something like this?

PubNub Web Page Best Practices
When user refreshes your web app page or navigates to another page there are things you need to consider as a web app developer no matter what technologies you may be using. I will address, at a high level, the things you need to do when PubNub is integrated into your web page.
Restore Parameter
Whether the user interrupts your connection to PubNub or it is a network failure, you will want PubNub to reconnect and continue where it left off as much as possible. The PubNub JavaScript SDK has a initialization parameter called restore that when set to true, will reconnect to PubNub and get missed messages after the connection is dropped and reestablished.
var pubnub = new PubNub({
subscribeKey: "mySubscribeKey",
publishKey: "myPublishKey",
ssl: true,
uuid: getUUID();
restore: true
});
Reuse UUID
It is important to reuse the same UUID for each end user as this will allow PubNub to identify that user uniquely when it comes to Presence so that it doesn't produce new join events for the same end user. The PubNub JavaScript SDK actually generates a UUID and stores it in localStrorage and reuses it by default but very likely you have your own UUID that you would like to use for each of your end users.
Last Message Received Timetoken
If the network disruption is brief as is the case with a page refresh or page navigation, then missed messages are retrieved when restore:true is implemented in the init as stated above. But when the user is offline for more than say 5 minutes, you may want to retrieve missed messages on one or more channels. The best way to do this is to keep track of the timetoken of the last received message by storing it in localStorage every time a message is received via subscribe callback. When the user comes back online and it is has been more than 5 minutes since they were last online, call history using this last received message timetoken on each channel that you need to get missed message from.
Subscribe to Channels
Finally, you'll want to make sure that the user is subscribed to the channel they expect to be based on what their state prior to the connection disruption. If it is a page refresh, you likely just want to resubscribe them to the same list of channels. To do this, you just need to keep a list of channels they are currently subscribed to, once again, in localStorage. If the user navigates to a new page and this causes a full page reload (modern web apps should not require this, but...) then you may want to unsubscribe from some channel(s) and subscribe to new channel(s), it just depends on what that page navigation means to your app. Modern web app frameworks do not require full page reload for page navigation since the web app acts more like a desktop app than older web apps. And again, if the the user was offline for quite some time (more than 5 minutes) then it may not make sense to subscribe them to the same channels that they were subscribed to before. Really depends on your use case.
And by the way, Tophatter uses PubNub ;) but all of the above are generic best practice guidelines and recommendations and is not referencing any one app in particular.
EDIT: To address you question specifically, as pointed out in comments below...
You can't implement long-running process in PubNub BLOCKS (not currently, anyways), so you will need a server process for this. When the user refreshes the page, you just need to hit your server for current state. If using PubNub to keep this progress bar updated in realtime, you just subscribe to that channel that is sending the state of that progress bar and update your client. Using the same best practices I provided above are still necessary.

Listener on a Web Page?

Is there a way for a web page to respond to a message from a web server, while idle? I need to display a page of user information. As a user swipes his card, a system will authenticate him, and then send a message to my solution, indicating that a user authenticated.
I then need to update a web page with his details. So, no interaction with the page from the user. It must just refresh when I send a message to it - somehow. Is this possible?
I was thinking of some sort of page which has 'subscribed' to events from a server, allowing me to send it, maybe a JSON object, and when it receives this message, refreshes the screen with the data from the messages it recieves?
We don't want to poll the server every second. We need to it respond to an incoming event. So, listening, as opposed to asking. and it has to be quick. So, the only delay would be the amount of time for the message to go from the web server, to the client browser.
We're using .Net application server, standard browser (Chrome, IE etc), a Bootstrap UI (Irrelevant, I guess).

is there a way for the server to save clients' addresses and send updates (for all or some clients) to an open html page?

here is what I want to do:
on a website: www.mySite.com
I want ppl to log on and be able to see other ppl who are currently viewing that webpage.
then I want them to be able to enter text on the webpage and it sends a message to the server
the server then sends this message to all the ppl viewing the page.
then I want the option to select a user from the list of users currently viewing the webpage.
and send that user alone a message (private messaging) but not all the others.
can I do this with html and php? I do NOT want to have a browser refreshing constantly to reload data.
I have looked into websocket technology and so far the only solutions I found is to open a socket connection, wait for a response from server and close the connection on timeout...
then reopen a new one and continously open and close sockets until updates are received by server.
is there a way for the client (browser) to listen for updates without polling a server?
-->>>is there a way for the server to save client addresses and send updates to an open html page (push data) to all those clients, only specific ones, or whatever the case is??<<--
html seems to work fine polling servers but then close connection right away.
Is there a way to keep a socket open indefinately, and not constantly reopen them to simulate server-browser push technology?
I am coding with a simple webserver using html, php and javascript. I am not paying for a virtual machine where I can construct services in my language of choosing.
I prefere not to use a 3rd party to achieve this.
I would like for this to be working on all browsers.
is this possible?

Send Request to browser from server (Java EE)

I want to send a request (or any response or notification) from the server side to the browser without a browser request to the server.
I use JSP and the Struts framework in my Java EE application. When some one is on my page, and when some processing in done in my action class/servlets, I want to send a notification or message or request to the browser to be appeared on the page. Here the relevant page cannot be refreshed or reloaded and it may be handled on the browser side with javascript or jquery. I use Http.
Is there a way to do this?
EDIT: Example: The application is an online inventory system. An Admin has logged in. If one of the items is out of stock, the admin should be notified saying that that particular item is out of stock without the admin searching the stores and do nothing (when he is on his account page, a pop up may be displayed to him).

I am not so sure what you meant but according to my understanding you can do this.I guess Comet is the thing you are looking for.Comet is the technique where in server pushes the data to the browser.

Try Pushlet concept which might address your requirement
http://www.javaworld.com/jw-03-2000/jw-03-pushlet.html