title: Cross-Domain AJAX REST service HTTP Headers
body: <p>I'm investigating the Cross-Domains problems, I have with some REST service call.
  Chrome said this:
  <strong>Request header field x-requested-with is not allowed by Access-Control-Allow-Headers</strong>
  This is what I've got from Network -> Headers tab:</p>
  
  <pre><code>Request URL: rest_url_on_other_domain
  Request Method:OPTIONS
  Status Code:200 OK
  Request Headers:
  Access-Control-Request-Headers:Origin, x-requested-with, content-type, accept
  Access-Control-Request-Method:POST
  Origin:http://localhost:8080
  
  Response Headers
  Access-Control-Allow-Headers:Content-Type, Accept
  Access-Control-Allow-Methods:GET, POST
  Access-Control-Allow-Origin:*
  Access-Control-Max-Age:1728000
  Cache-Control:no-cache, no-store
  Connection:keep-alive
  Content-Length:0
  Date:Fri, 30 Dec 2011 11:29:12 GMT
  Expires:-1
  Pragma:no-cache
  Server:nginx/1.0.2
  </code></pre>
  
  <p>Could somebody explain about this HTTP Headers? What is the problem - <strong>Some headers check on the server fail or some headers check on the client side (browser) fail</strong>. What's the very idea about this Access headers? Explain in detail in simple words just to get the feeling the rest I'll learn by my self. Thanks in advance!</p>