title: Check dynamic page if changed on php via curl or other way
body: <p>i have a question for checking : "is page content changed?". etag is very good solution but i want to checking any url if developer of web page used etag or not. and i dont want to download full page before if it is not changed. it is possible static file with <code>last-modified</code> meta via curl but it is not possible on dynamic page if developer didn't use etag or any method.</p>
  
  <p>i dont want to use <code>md5(file_get_content("http://.."))</code> or same way.</p>
  
  <p>solution must like <code>curl --head http://.... | grep ..| awk ..</code></p>
  
  <p>sorry for language,
  Thanks,</p>