使用JavaScript访问缓存响应头

// 使用XMLHttpRequest对象
var xhr = new XMLHttpRequest();
xhr.open('GET', 'https://example.com/api/data', true);
xhr.setRequestHeader('Cache-Control', 'no-cache');
xhr.onreadystatechange = function() {
  if (xhr.readyState === 4 && xhr.status === 200) {
    var headers = xhr.getAllResponseHeaders();
    console.log(headers);
    var cacheControl = xhr.getResponseHeader('Cache-Control');
    console.log(cacheControl);
  }
};
xhr.send();

// 使用fetch API
fetch('https://example.com/api/data', {
  method: 'GET',
  headers: {
    'Cache-Control': 'no-cache'
  }
})
.then(function(response) {
  var headers = response.headers;
  console.log(headers);
  var cacheControl = headers.get('Cache-Control');
  console.log(cacheControl);
});