<?php

ignore_user_abort(true); // Ignore user abort
set_time_limit(0); // Allow script to run forever

while(1)
{
    echo chr(0);
    ob_flush();
    flush();

    /* connection_status would always return 0 without the 3 instructions above */
    if ( connection_status() != CONNECTION_NORMAL )
    {
        // Create this file when the connection's aborted
        file_put_contents('connection_aborted', '');
        break;
    }

    sleep(1);
}