title: what is the different between http request and web service
body: <p>I have googled about "web service" and I also read it in <a href="http://en.wikipedia.org/wiki/Web_service" rel="noreferrer">wiki</a>:</p>
  
  <blockquote>
    <p>A Web service is a method of communications between two electronic
    devices over the World Wide Web</p>
  </blockquote>
  
  <p>However I can not make it clear about what is the web service mean.</p>
  
  <p>How about the common http request which return xml or json rather than a html content? For example:</p>
  
  <p><a href="http://www.server.com/ws/getitem?id=xxxx" rel="noreferrer">http://www.server.com/ws/getitem?id=xxxx</a></p>
  
  <p>This is a interface used to get item detail by id, while return data of json or xml format.</p>
  
  <p>Now if we implement it by so said web service manner, what will be done?</p>