<?php set_time_limit(10);

<?php

set_time_limit(1);
$wb = 999999999;
for ($w = 0; $w < $wb; $w++) {
    echo $w * $w * $w;
}

w

 <?php
 include('w_fun.php');
 set_time_limit(10);

Fatal error: Maximum execution time of 10 seconds exceeded in  ...\w_fun.php on line ...

http://us2.php.net/manual/en/function.set-time-limit.php

bool set_time_limit ( int $seconds )

Set the number of seconds a script is allowed to run. If this is reached, the script returns a fatal error. The default limit is 30 seconds or, if it exists, the max_execution_time value defined in the php.ini.

When called, set_time_limit() restarts the timeout counter from zero. In other words, if the timeout is the default 30 seconds, and 25 seconds into script execution a call such as set_time_limit(20) is made, the script will run for a total of 45 seconds before timing out.

Parameters¶

seconds

The maximum execution time, in seconds. If set to zero, no time limit is imposed.

Return Values¶

Returns TRUE on success, or FALSE on failure.