php全等运算符 ===

<?php
    /* php全等 === */
    $a = 2;
    $b = 2.0;
    
    if ($a == $b) 
        echo "ok";        // ok
    
    if ($a === $b)
        echo "ok";
?>
== 只要求值相等
=== 要求值和类型都相等