在javascript中检测其他网站是否在线

function checkWebsiteStatus(url) {
  return new Promise((resolve, reject) => {
    const xhr = new XMLHttpRequest();
    xhr.open('GET', url);
    xhr.onload = function() {
      if (xhr.status === 200) {
        resolve('Website is online');
      } else {
        reject('Website is offline');
      }
    };
    xhr.onerror = function() {
      reject('Website is offline');
    };
    xhr.send();
  });
}

const websiteUrl = 'https://www.example.com';
checkWebsiteStatus(websiteUrl)
  .then((result) => {
    console.log(result);
  })
  .catch((error) => {
    console.error(error);
  });