向Ajax请求添加标头

var xhr = new XMLHttpRequest();
xhr.open("GET", "https://example.com/api/data");
xhr.setRequestHeader("Authorization", "Bearer " + token);
xhr.send();

var headers = new Headers();
headers.append("Authorization", "Bearer " + token);
fetch("https://example.com/api/data", {
  method: "GET",
  headers: headers
})
.then(response => response.json())
.then(data => console.log(data))
.catch(error => console.error(error));