JAVASCRIPT:
a. 代码:

var a = function(){}var my_a = new a()my_a.say = function(){console.log('hello')}my_a.say()

b. 输出:

helloPHP:
a. 代码:

<?phpclass a{}$a = new a();$a->say = function(){echo "hello";};$say = $a->say;$say();

b. 输出:

hello