nginx服务器配置解决ajax的跨域问题

在采用jquery ajax调用http请求时，发现了一系列问题：

如采用firebug调试api请求（这个api是自己服务器的应用），看到服务器明明返回200状态，response返回数据也是json格式，但ajax返回的error。

在排除json数据格式不正确的原因之后，发现了ajax error函数返回“networkerror failed to execute ‘send' on ‘xmlhttprequest' failed to load ‘http //“ xmlhttprequest.status=0，就是没有初始化。

后来才知道是跨域问题（cors），因为程序调用的是远程服务器的api，服务器不允许跨域调用。如果只是简单的方法，只需要在程序的response添加支持跨域的header添加属性”access-control-allow-origin: *“即可。如java 服务器代码：

yourownvariable.setheader("access-control-allow-origin:", "origin url of your site");

yourownvariable.setheader("access-control-allow-methods", "get, post,put");

如果是配置nginx服务器（如果是其他服务器，可以参考：i want to add cors support to my server），需要在nginx.conf配置文件添加一下内容：

#
# wide-open cors config for nginx
#
location / {
if ($request_method = 'options') {
add_header 'access-control-allow-origin' '*';
add_header 'access-control-allow-methods' 'get, post, options';
#
# custom headers and headers various browsers *should* be ok with but aren't
#
add_header 'access-control-allow-headers' 'dnt,x-customheader,keep-alive,user-agent,x-requested-with,if-modified-since,cache-control,content-type,content-range,range';
#
# tell client that this pre-flight info is valid for 20 days
#
add_header 'access-control-max-age' 1728000;
add_header 'content-type' 'text/plain charset=utf-8';
add_header 'content-length' 0;
return 204;
}
if ($request_method = 'post') {
add_header 'access-control-allow-origin' '*';
add_header 'access-control-allow-methods' 'get, post, options';
add_header 'access-control-allow-headers' 'dnt,x-customheader,keep-alive,user-agent,x-requested-with,if-modified-since,cache-control,content-type,content-range,range';
add_header 'access-control-expose-headers' 'dnt,x-customheader,keep-alive,user-agent,x-requested-with,if-modified-since,cache-control,content-type,content-range,range';
}
if ($request_method = 'get') {
add_header 'access-control-allow-origin' '*';
add_header 'access-control-allow-methods' 'get, post, options';
add_header 'access-control-allow-headers' 'dnt,x-customheader,keep-alive,user-agent,x-requested-with,if-modified-since,cache-control,content-type,content-range,range';
add_header 'access-control-expose-headers' 'dnt,x-customheader,keep-alive,user-agent,x-requested-with,if-modified-since,cache-control,content-type,content-range,range';
}
}