- microtime: documentation ( source)
<?php
$v1 = 5;
$v2 = '5-4';
$time = microtime(1);
$i = 0;
while($i++ < 1000000) echo '','','','','';
echo (microtime(1)-$time)." seconds for commas";
echo "\n";
$time = microtime(1);
$i = 0;
while($i++ < 1000000) echo ''.''.''.''.'';
echo (microtime(1)-$time)." seconds for dot";