XMLHtt prequest状态0（responseText的是空） [英] XMLHttpRequest status 0 (responseText is empty)

问题描述

不能与XMLHtt prequest数据（状态0和responseText的是空的）：

Cannot get data with XMLHttpRequest (status 0 and responseText is empty):

xmlhttp=new XMLHttpRequest();
xmlhttp.open("GET","http://www.w3schools.com/XML/cd_catalog.xml", true);
xmlhttp.onreadystatechange=function() 
{
  if(xmlhttp.readyState==4)
    alert("status " + xmlhttp.status);
}
xmlhttp.send();

据警报状态0。

It alerts "status 0".

同样的情况与本地主机请求（cd_catalog.xml保存为本地文件）

The same situation with the localhost request (cd_catalog.xml is saved as a local file)

xmlhttp.open("GET","http://localhost/cd_catalog.xml", true);

但与本地主机的IP请求

But with the localhost IP request

xmlhttp.open("GET","http://127.0.0.1/cd_catalog.xml", true);

和使用本地文件的请求

xmlhttp.open("GET","cd_catalog.xml", true);

一切正常（状态200）

everything is OK (status 200)

有什么可以与在线请求导致问题（状态= 0）？

What can cause the problem (status=0) with the online request?

PS：现场HTTP头显示，一切正常在所有4个情况：

PS: Live HTTP Headers shows that everything is OK in all 4 cases:

  HTTP/1.1 200 OK
  Content-Length: 4742

PS2：在VMWare（主机操作系统Win7的，客户机操作系统Ubuntu的，网络适配器 - NAT）的Apache本地Web服务器。浏览器 - 火狐

PS2: Apache local web server on VMWare (host OS Win7, Guest OS Ubuntu, Network adapter – NAT). Browser – Firefox.

推荐答案

你的问题的原因是您正在尝试做一个跨域调用和失败

如果你正在做本地主机的发展可以使跨域调用 - 我做这一切的时候。

If you're doing localhost development you can make cross-domain calls - I do it all the time.

对于Firefox，您必须启用它在你的配置设置

For Firefox, you have to enable it in your config settings

signed.applets.codebase_principal_support = true

然后添加像这样的东西你XHR开放code：

Then add something like this to your XHR open code:

  if (isLocalHost()){
    if (typeof(netscape) != 'undefined' && typeof(netscape.security) != 'undefined'){
      netscape.security.PrivilegeManager.enablePrivilege('UniversalBrowserRead');
    }
  }

有关IE浏览器，如果我记得没错，你所要做的就是让下浏览器的安全设置杂项与RARR;跨域访问数据源得到它使用ActiveX XHRs工作。

For IE, if I remember right, all you have to do is enable the browser's Security setting under "Miscellaneous → Access data sources across domains" to get it to work with ActiveX XHRs.

IE8及以上还增加了跨域功能，本机XmlHtt prequest对象，但我还没有玩过这些呢。

IE8 and above also added cross-domain capabilities to the native XmlHttpRequest objects, but I haven't played with those yet.

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