AJAX Ready State 4, but empty text_问答_开发者

开发者 https://www.devze.com 2023-02-26 17:41 出处：网络

I call a page using AJAX, requesting a search for something. But the response text is always empty, although the ready state is 4.

相关专题：http

I call a page using AJAX, requesting a search for something. But the response text is always empty, although the ready state is 4.

function process() {
 var requestPage = "http://some.page/search.php";
 var xmlHTTP;
 var searchString = "test";

 if (window.XMLHttpRequest) {
  xmlHTTP = new XMLHttpRequest开发者_如何学Python();
 } else {
  xmlHTTP = new ActiveXObject("Microsoft.XMLHTTP");
 }

 var results;

 xmlHTTP.open("GET", requestPage + "?search=" + searchString, true);
 xmlHTTP.send();

 xmlHTTP.onreadystatechange = function() {
   results = xmlHTTP.responseText;
   alert("r: " + results + " rs: " + xmlHTTP.readyState + " st: " + xmlHTTP.status);
 }
}

The results I get from this are

r: rs: 2 st: 0
r: rs: 4 st: 0

So, the request is done successfully, but the HTTP status isn't 200. But: I tracked the request using WireShark and the result package of the request shows as status 200 and even contains the complete result of the request, see below:

7014    190.663287  some.page   local.pc    HTTP    HTTP/1.1 200 OK  (text/html)
HTTP/1.1 200 OK
Server: Apache-Coyote/1.1
Set-Cookie: JSESSIONID=xxx; Path=/xxx
Content-Type: text/html;charset=iso-8859-1
Content-Length: 3108
Date: Tue, 19 Apr 2011 13:05:41 GMT
<html>
<head>
<title>Search</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>
<body bgcolor="white">
...

So; why don't I get the status 200 on my AJAX request when it obviously succeded?

So your problem is that you are requesting a page with a different port.
The same origin policy says that the protocol, port and host should be the same.
See
http://en.wikipedia.org/wiki/Same_origin_policy and https://developer.mozilla.org/en/Same_origin_policy_for_JavaScript