js加载功能的实现

var xhr = new XMLHttpRequest();
xhr.open('GET', 'your-url', true);
xhr.onload = function() {
    if (xhr.status === 200) {
        console.log(xhr.responseText);
    } else {
        console.error('Error loading data');
    }
};
xhr.send();

fetch('your-url')
    .then(response => {
        if (!response.ok) {
            throw new Error('Network response was not ok');
        }
        return response.json();
    })
    .then(data => console.log(data))
    .catch(error => console.error('There has been a problem with your fetch operation:', error));

async function loadData() {
    try {
        const response = await fetch('your-url');
        if (!response.ok) {
            throw new Error('Network response was not ok');
        }
        const data = await response.json();
        console.log(data);
    } catch (error) {
        console.error('There has been a problem with your fetch operation:', error);
    }
}

loadData();

let isLoading = false;

async function loadData() {
    if (isLoading) return; // 防止重复请求
    isLoading = true;
    showLoadingSpinner(); // 显示加载动画

    try {
        const response = await fetch('your-url');
        if (!response.ok) throw new Error('Network response was not ok');
        const data = await response.json();
        updateUI(data); // 更新页面内容
    } catch (error) {
        showError(error.message); // 显示错误信息
    } finally {
        isLoading = false;
        hideLoadingSpinner(); // 隐藏加载动画
    }
}