I need an urgent help regarding iframe and PHP.

[sameeroaf]

I’m sorry if I’m asking about something already asked before.
I’m trying to use iframe in a php page using BV, and make it call a random page from my website. I tried to put this code everywhere I know, inside the (iframe HTML) and also inside the (page HTML), but it did not work.
Can anyone help me please, I need it very badly.
Here is the code:
<?php

$random=mt_rand(1,3); //this gives a random number between 1 and 3

switch($random)
{
case 1:
include('htmldoc1.html');
break;

case 2:
include('htmldoc2.html');
break;


case 3:
include('htmldoc3.html');
break;
}
?>

Thanks in advance.