js获取当前页面的源码

let pageSource = document.documentElement.outerHTML;
console.log(pageSource);

fetch(window.location.href)
  .then(response => response.text())
  .then(pageSource => {
    console.log(pageSource);
  })
  .catch(error => {
    console.error('Error fetching the page:', error);
  });

let xhr = new XMLHttpRequest();
xhr.open('GET', window.location.href, true);
xhr.onreadystatechange = function() {
  if (xhr.readyState === 4 && xhr.status === 200) {
    let pageSource = xhr.responseText;
    console.log(pageSource);
  }
};
xhr.send();