title: Validate HTTP request came from tap on NFC tag
body: <p>A typical scenario encodes a tag with a URL. Tapping the tag makes an HTTP request which is resolved by the web server. Can I (we) determine the tap actually came from tapping the tag rather than requesting the URL using a bookmark or typing the URL into the address bar of a browser?</p>
  
  <p>In the context of my question I need to learn how the mobile devices know what to do with the tap, i.e. what is the mechanism which makes the HTTP request?</p>
  
  <p>In the context of my questions I need to learn if there is a way to do validation in this context knowing that HTTP_REFERER requires a click event to populate the variable with data. Is the tap a click event? Is the tap event driven?</p>
  
  <p>I have C# and client-side scripting skills and will be hosting the URLs on a Windows server using nopCommerce developed with C# using MVC and the tags will of course be just about anywhere but I need to learn if there is a way to validate the tag was actually tapped to issue the HTTP request.</p>