background music Any expert in xibo can figure out this

In xibo client we setup xampp to handle php code. on
/opt/lampp/htdocs/sound/enable.php

<?php
$file = fopen("test.txt","w");
echo fwrite($file,"1");
fclose($file);
?>
This PHP code open our existing file test.txt and write 1 into it.

/opt/lampp/htdocs/sound/disable.php

<?php
$file = fopen("test.txt","w");
echo fwrite($file,"0");
fclose($file);
?>
This PHP code open our existing file test.txt and write 0 into it.

From server we used 2 layout for this testing. on layout1 we add 1 region with webpages link=http://localhost/sound/enable.php and on layout2 we add 1 region with webpages link=http://localhost/sound/disable.php.
What we want to accomplish is when xibo client running displaying layout1 the file /opt/lampp/htdocs/sound/test.txt should have 1 into it and then when displaying layout2 test.txt should have 0 into it.
 Observation: the code is running and writed 1 to test.txt when current display is layout1,
then if change to layout2 write 0, when it go back to layout1 the test.txt not change is remain to 0, meaning it run only once. what possible reason why this happen supposed test.txt should change sequence to write 1 if layout1 0 if layout2 and again. . . . so I can call my shell script when 1 run script for audio background if 0 then disable audio background.

thanks