PHP method to detect whether the user has closed the browser

echo str_repeat(" ",3000);
ignore_user_abort(true); 
mylog('online');
while (true) {
   /*
   * 1、程序正常结束   connection_status 0
   * 2、点击浏览器“停止”按钮   connection_status 1
   * 3、超时  connection_status 2
   */
 echo "test<br>\n"; //注意程序一定要有输出，否则ABORTED状态是检测不到的
 flush();
 sleep(1);
 if (connection_status()!=0){
    mylog('offline');
    die('end the script');
 }
}
function mylog($str)
{
   $fp = fopen('e:/abort.txt', 'a');
   $str = date('Y-m-d H:i:s').$str."\r\n";
   fwrite($fp, $str);
   fclose($fp);
}

function foo() {
 $s = 'connection_status '. connection_status();
 mylog($s);
} 
register_shutdown_function('foo');//script processing is complete or when exit() is called
set_time_limit(10);
for($i=0; $i<10000000; $i++)
 echo $i;
function mylog($str)
{
  $fp = fopen('e:/abort.txt', 'a');
  $str = date('Y-m-d H:i:s').$str."\r\n";
  fwrite($fp, $str);
  fclose($fp);
}