The usleep() function delays program execution for the given number of micro_seconds. A microsecond is one millionth of a second.
<?php
// Current time
echo date('h:i:s') . "\n";
// wait for 2 secondes
usleep(2000000);
// back!
echo date('h:i:s') . "\n";
?>
This script will output :
11:13:28
11:13:30
This function did not work on Windows systems until PHP 5.0.0
See also sleep() and set_time_limit().