The passed parameters can be modified in the function in Javascript, as shown below

function func1(name) {
    name = 'lily';
    alert(name);
}
func1('jack');//Output lily

Let’s do another example

function fun1(n) {
    this.name = n;
}
function fun2(name) {
    fun1.call(this,'lily');
    alert(name);
}
fun2("jack");//Output "jack"

The fun1 function tried to change the argument to “lily” when fun2 was called, but failed. The popup is still “jack”. Think about why?

In fact, fun1 has the ability to change the parameters of the call to fun2, using the caller property

function fun1() {
    arguments.callee.caller.arguments[0] = 'lily';
}
function fun2(name) {
    fun1.call(this,name);
    alert(name);
}
fun2("jack");//Output "lily"

As you can see, the outer function is visible and modifiable to the call stack of the inner function.