js经典代码

alert('Hello, World!');

document.getElementById('myElement').innerHTML = 'New Content';

document.getElementById('myButton').addEventListener('click', function() {
    alert('Button was clicked!');
});

setInterval(function() {
    console.log('This message will appear every second.');
}, 1000);

var person = {
    firstName: "John",
    lastName: "Doe",
    age: 30,
    fullName: function() {
        return this.firstName + " " + this.lastName;
    }
};

console.log(person.fullName()); // 输出: John Doe

var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function() {
    if (xhr.readyState == 4 && xhr.status == 200) {
        document.getElementById('result').innerHTML = xhr.responseText;
    }
};
xhr.open('GET', 'https://api.example.com/data', true);
xhr.send();

function fetchData() {
    return new Promise((resolve, reject) => {
        setTimeout(() => resolve("Data fetched!"), 2000);
    });
}

fetchData().then(data => console.log(data));

const numbers = [1, 2, 3, 4, 5];
const doubled = numbers.map(n => n * 2);
console.log(doubled); // 输出: [2, 4, 6, 8, 10]