Backend determines whether the user closes the browser (closes all tab related to the site)

A) procedure steps

1, JS write a timed request back end (PHP), the backend received a request to, the current timestamp write to the file

2, PHP blocking, here I write 3 seconds, that is, sleep (3)

3, get the current time and the time in the file for comparison, if the time interval is 3 seconds, it means that the front end has not been requested, as the user closed all the site-related tab

II) Realization principle

First of all, every request comes in, immediately update the timestamp in the file, and then block the program for 3 seconds;

Well, if I set the front-end of the timing request is 2 seconds, the second request came over, in fact, the first request has not been processed (because blocked for 3 seconds);

When the first request blocking the end, down execution, the time stamp in the file has been modified by the first request, then the current time to reduce the time stamp in the file, the interval is certainly not 3 seconds;

Conversely, if the interval is reduced to 3 seconds, it means that the file timestamp has not been modified, that is, there is no next request, as the user closed the site link, then can do log records such as Logout

c) part of the Code

Js:

functionTest (URL) {varXMLHTTP =NewXMLHttpRequest (); Xmlhttp.onreadystatechange=function(){        if(xmlhttp.readystate==4){            if(xmlhttp.status==200){                //Console.log (xmlhttp.responsetext);}}} xmlhttp.open ("GET", URL,true); Xmlhttp.setrequestheader ("Content-type", "application/x-www-form-urlencoded"); Xmlhttp.send (NULL);} Window.setmyinterval=function(func, interval) {varNexttime =interval; varStart =NewDate (). GetTime (); varnow =NULL; varToffset = 0; vari = 0; varGoGoGo =function() {window.settimeout (function() {i++; now=NewDate (). GetTime (); Toffset= Now-(Start + i *interval); Nexttime= Interval-Toffset;            Func ();        GoGoGo ();    }, Nexttime);    }; GoGoGo ();}vari = 0; Window.setmyinterval (function() {Test (' Test ' + ((i%2) +1) + '. php '); I++;}, 2000); Test (' test2.php ');

Php:

test1.php

<? PHP file_put_contents  Time ()); Sleep (3); $t 1                file_get_contents (' User1_time.txt '); $now             Time (); if ($now$t 1 = = 3)    {error_log("SUCCESS", 3, "Debug.txt")    ; unlink (' User1_time.txt ');}? >

test2.php

<? PHP require (' test1.php ');? >

I think of the way to do that, modify it according to the actual requirements of the project

Finish

Backend determines whether the user closes the browser (closes all tab related to the site)