JavaScript 获取 URL 中参数值的方法

https://example.com/page?name=alice&age=25

// 假设当前 URL 为：https://example.com/page?name=alice&age=25
// 获取查询字符串（问号后面的部分）
const queryString = window.location.search;
// 创建 URLSearchParams 实例
const params = new URLSearchParams(queryString);
// 获取单个参数的值
const name = params.get('name'); // "alice"
const age = params.get('age');   // "25"
console.log('Name:', name);
console.log('Age:', age);

function getQueryParam(param) {
  const url = window.location.href;
  // 构造正则表达式，匹配 ? 或 & 后面跟随的参数名称和其值
  const regex = new RegExp('[?&]' + param + '=([^&#]*)', 'i');
  const result = regex.exec(url);
  return result ? decodeURIComponent(result[1]) : null;
}
// 假设 URL 为：https://example.com/page?name=alice&age=25
console.log(getQueryParam('name')); // "alice"
console.log(getQueryParam('age'));  // "25"

function parseQueryString(queryString) {
  const params = {};
  // 移除问号
  queryString = queryString.replace(/^\?/, '');
  // 分割成键值对数组
  const pairs = queryString.split('&');
  pairs.forEach(pair => {
    if (!pair) return;
    const [key, value] = pair.split('=');
    const decodedKey = decodeURIComponent(key);
    const decodedValue = value ? decodeURIComponent(value) : '';
    // 如果键已经存在，则将其转换为数组
    if (params[decodedKey]) {
      if (Array.isArray(params[decodedKey])) {
        params[decodedKey].push(decodedValue);
      } else {
        params[decodedKey] = [params[decodedKey], decodedValue];
      }
    } else {
      params[decodedKey] = decodedValue;
    }
  });
  return params;
}
// 示例：URL 为：https://example.com/page?name=alice&age=25&hobby=reading&hobby=swimming
const queryString = window.location.search;
const queryParams = parseQueryString(queryString);
console.log(queryParams);
// 输出: { name: "alice", age: "25", hobby: ["reading", "swimming"] }