java-web/examples/chapter03/app.js

document.addEventListener('DOMContentLoaded', function() {
    // GET 请求按钮
    const getButton = document.getElementById('getButton');
    // 显示 GET 请求结果的区域
    const getResults = document.getElementById('getResults');

    // POST 请求表单
    const postForm = document.getElementById('postForm');
    // 显示 POST 请求结果的区域
    const postResults = document.getElementById('postResults');

    // GET 请求函数
    getButton.addEventListener('click', function() {
        fetch('https://jsonplaceholder.typicode.com/posts')
            .then(response => response.json())
            .then(data => {
                displayResults(getResults, data);
            })
            .catch(error => {
                console.error('Error fetching data:', error);
                displayResults(getResults, { error: 'An error occurred while fetching data.' });
            });
    });

    // POST 请求函数
    postForm.addEventListener('submit', function(event) {
        event.preventDefault();
        const title = document.getElementById('title').value;
        const body = document.getElementById('body').value;
        const userId = document.getElementById('userId').value;

        const postData = {
            title: title,
            body: body,
            userId: userId
        };

        fetch('https://jsonplaceholder.typicode.com/posts', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json; charset=UTF-8',
            },
            body: JSON.stringify(postData),
        })
            .then(response => response.json())
            .then(data => {
                displayResults(postResults, data);
            })
            .catch(error => {
                console.error('Error posting data:', error);
                displayResults(postResults, { error: 'An error occurred while posting data.' });
            });
    });

    // 显示结果的函数
    function displayResults(element, data) {
        element.querySelector('.card-text').textContent = '';
        if (Array.isArray(data)) {
            data.forEach(item => {
                element.querySelector('.card-text').appendChild(document.createTextNode(`ID: ${item.id}<br>`));
                element.querySelector('.card-text').appendChild(document.createTextNode(`Title: ${item.title}<br>`));
                element.querySelector('.card-text').appendChild(document.createTextNode(`Body: ${item.body}<br>`));
                element.querySelector('.card-text').appendChild(document.createTextNode(`User ID: ${item.userId}<br>`));
                element.querySelector('.card-text').appendChild(document.createElement('hr'));
            });
        } else {
            for (let key in data) {
                element.querySelector('.card-text').appendChild(document.createTextNode(`${key}: ${data[key]}<br>`));
            }
        }
    }
});