title: using ajax to post to php file - security
body: <p>I am developing iOS app using phonegap.
  Users first have to register or log in. (ajax: post to php file on my webserver, like here: <a href="https://stackoverflow.com/questions/3336636/php-ajax-login-is-this-method-secure">PHP AJAX login, is this method secure?</a>).</p>
  
  <p>Info needs to be sent to mySQL database, users can upload pictures, ... </p>
  
  <p>Now I was wondering if there is a way to prevent other people from posting to my php files.</p>
  
  <p>In my opinion, it would be quite simple to make some script to add thousands of fake accounts, or upload thousands of pictures.</p>
  
  <p>I read: <a href="https://stackoverflow.com/questions/1936146/post-method-ajax-and-security">POST method, Ajax and Security?</a>, but I don't seem to find a way to implement this in a phonegap app.</p>
  
  <p>How do I make sure I am the only one who can use these php files?</p>