Amusing JS vs. PHP comparison

foo.js

(function foo(x) {
   return function bar() {
      alert(x);
   };      
})("foo");

(function foo(x) {
   return function bar() {
      alert(x);
   };      
})("foo")();

foo.php

<?php

call_user_func(function foo($x) { 
    return function bar() use ($x) {
        echo $x;
    };
}, "foo");

call_user_func(call_user_func(function foo($x) { 
    return function bar() use ($x) {
        echo $x;
    };
}, "foo"));