javascript - The relationship between callback functions and closures

Question

Does the callback function use the closure feature? for example:

$('button').onclick = function(){ /* do sth */};

Answer 1

A=(x)=>{alert(x)};
B=(callback)=>{
let y=1;
callback(y)
};
B(A);
This way the callback is Used it

Answer 2

No, there is no closure here.

Closure returns function B in function A, and function B always references the layout variable of function A.