PHP : empty vs == vs ===

sample.php

<?php

$t = '';

$before = microtime(true);

for ($i=0 ; $i<100000 ; $i++) {
    $dummy = empty( $t );
}

$after = microtime(true);

echo 'empty : ' . ( $after - $before );

echo "\n";

$before = microtime(true);

for ($i=0 ; $i<100000 ; $i++) {
    $dummy = $t == '';
}

$after = microtime(true);

echo '== "" : ' . ( $after - $before );

echo "\n";

$before = microtime(true);

for ($i=0 ; $i<100000 ; $i++) {
    $dummy = $t === '';
}

$after = microtime(true);

echo '=== "" : ' . ( $after - $before );