js中for循环和ajax

for (初始化; 条件; 迭代) {
    // 循环体
}

let numbers = [1, 2, 3, 4, 5];
for (let i = 0; i < numbers.length; i++) {
    console.log(numbers[i]);
}

fetch('https://api.example.com/data')
    .then(response => response.json())
    .then(data => console.log(data))
    .catch(error => console.error('Error:', error));

let urls = ['url1', 'url2', 'url3'];

for (let i = 0; i < urls.length; i++) {
    fetch(urls[i])
        .then(response => response.json())
        .then(data => console.log(`Data from ${urls[i]}:`, data))
        .catch(error => console.error(`Error fetching ${urls[i]}:`, error));
}

let promises = urls.map(url => fetch(url).then(response => response.json()));

Promise.all(promises)
    .then(results => results.forEach((data, index) => console.log(`Data from ${urls[index]}:`, data)))
    .catch(error => console.error('Error:', error));

for (let i = 0; i < urls.length; i++) {
    (function(index) {
        fetch(urls[index])
            .then(response => response.json())
            .then(data => console.log(`Data from ${urls[index]}:`, data));
    })(i);
}

for (let i = 0; i < urls.length; i++) {
    fetch(urls[i])
        .then(response => response.json())
        .then(data => console.log(`Data from ${urls[i]}:`, data));
}