6-3 例子

1、

var test = function(num){
            console.log(num);
            var num =30;
}
test();

2、

 var test = function(num){
            console.log(num);
            var num =20;
            function num(){
                console.log("hello world")
            }
}
test(10);

3、

var test = function(num){
    console.log(num);
    var num =20;
    function num(){
        console.log("hello world")
    }
    console.log(num)
}
test(10);