I'm building a mobile app which will call a search engine on my website. I have PHP code to detect if a person is coming in through a Mobile device. However, I want to see if I can detect if they are coming in through my app versus a regular page browse.

In the past, I've had a hidden field on a form submission, but this is not feasible anymore.

I want to know if there is a way if somebody accesses a page on my website through the mobile app or a mobile browser?

One option is to pass a PHP $\_GET parameter, but I'm looking for other solutions.