php和javascript如何执行嵌套函数的区别

Question

我试图想象 javascript 和 php 如何处理嵌套函数。重点是：php :b(); //CANNOT call b at this point because isn't defined yeta(); //CAN call a at this point because the interpreter see the declarb(); //ok now i can call b, because the interpreter see the declaration after a executionfunction a(){    function b(){        echo "inner";    }}同时在javascript 中：b(); //CANNOT call b isn't defined yeta(); //CAN call a at this point because the interpreter see the declarfunction a(){    function b(){        console.log("inner");    }}a(); //ok now i can call a because is definedb(); // **CANNOT** call b yet !!   为什么在 javascript 中即使 a 被执行我也不能调用 b() ？PHP 在哪些方面表现不同？