js如何获取response header信息

Question

js如何获取response header信息, 用sessionstatus=XMLHttpRequest.getResponseHeader("sessionStatus"); 获取到的为null。麻烦大侠们看看怎么解决，截图如下：

Answer 1

var req = new XMLHttpRequest();

req.open('GET', document.location, false);

req.send(null);

var headers = req.getAllResponseHeaders().toLowerCase();

alert(headers);