【js】请写出如下代码的打印结果

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【js】请写出如下代码的打印结果 #55

Open misty0304 opened 4 years ago

misty0304 commented 4 years ago

var name = 'Tom';
(function() {
    if (typeof name == 'undefined') {
        var name = 'Jack';
        console.log('Goodbye ' + name);
    } else {
        console.log('Hello ' + name);
    }
})();

var name = 'Tom';
(function() {
    if (typeof name == 'undefined') {
        let name = 'Jack';
        console.log('Goodbye ' + name);
    } else {
        console.log('Hello ' + name);
    }
})();

misty0304 commented 4 years ago

1.Goodbye Tom：var变量提升

Hello Tom：let块级作用域