Show Time difference in milliseconds using PHP

Dear Friends,
We might have come across showing results by google with search time. The same can be implemented in our program as well.

<?php

$currentTime = microtime(true);


// Write some code which consume your CPU time
//...
// Find time difference in milliseconds

$timediff= round(microtime(true) - $currentTime,3)*1000;
echo "<h4>in ". $timediff. " Milli seconds </h4><br>";

?>