php判断客户端浏览器是否已经断开连接

<? php
date_default_timezone_set( ' asia/shanghai ' );
$starttime = date ( ' h:i:s ' );
set_time_limit ( 30 );
echo ' ignore_user_abort: ' . ignore_user_abort () . ' <br> ' ;
ignore_user_abort ( true );
echo ' ignore_user_abort: ' . ignore_user_abort () . ' <br> ' ;
$i = 1 ;
while ( 1 ){
if ( ! connection_aborted ()){
echo " hello!!!--$i<br> " ;
ob_flush ();
flush ();
sleep ( 1 );
$i ++ ;
} else {
$endtime = date ( ' h:i:s ' );
$status = ' seconds: ' . " $i connectionstatus: " . connection_status () . " connection_aborted: " . connection_aborted ();
file_put_contents ( ' stop.txt ' , " $starttime->$endtime:stop $status " );
exit ();
}
}
?>