XHR responseText 是空字符串-前端问题

XHR responseText is empty string(XHR responseText 是空字符串)

本文介绍了XHR responseText 是空字符串的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

HTML页面:

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>xhr</title>
</head>
<body>
    <script>
        var xhr_test = new XMLHttpRequest();
        xhr_test.open("GET","xhrtest",true);
        xhr_test.send();
        alert(xhr_test.responseText);
    </script>
</body>
</html>

main.py 文件:

The main.py file:

import webapp2
from handlers import cookies,pages
application = webapp2.WSGIApplication([
        ('/xhr',pages.XHR),
        ('/xhrtest', cookies.XHRTest)
        ],
            debug=True)

请求处理程序:

class XHRTest(webapp2.RequestHandler):
    def get(self):
        self.response.write('0')

和，

class XHR(webapp2.RequestHandler):
    def get(self):
        f = open('static/html/xhr.html','r')
        self.response.write(f.read())

现在，当我点击 URL localhost:8080/xhrtest 时，浏览器会立即将响应 0 显示为页面内容.

Now, when I hit upon the url localhost:8080/xhrtest the browser promptly shows the response 0 as the page's content.

点击url localhost:8080/xhr间接点击/xhrtest，在alert框中弹出一个空字符串(responseText是一个空字符串)但是检查在network标签下chrome的response标签，可以看到请求的响应是0.

Hitting the url localhost:8080/xhr which indirectly hits /xhrtest, pops up an empty string in the alert box (the responseText is an empty string) but checking chrome's response tab under the network tab, I can see that the request's response is 0.

那么为什么 xhr_test.responseText 不能显示相同的响应?

So why is xhr_test.responseText not able to display the same response?