Fancy's way of detecting if app exists and launching app accordingly. It does referrer checking to see if the link is coming from email, and only does it then.

detect_app.js

<script>
var thing_id = "441444475001111765";
$('.thing-related-photo img').each(function(){
   if($(this).width()>$(this).height()){
     $(this).css("height","60px");
   }else{
	   $(this).css("width","60px");
   }
});

jQuery(function($){
	var ref = "";
	if(/ref=/.test(location.search)){
		ref = "?ref="+(location.search).match(/ref=([^&]*)?/)[1];			
	}
	$('#header a.app').attr('href','intent://things/'+thing_id+ref+'#Intent;scheme=fancy;package=com.thefancy.app;end');
	if(!document.referrer) $('<iframe>').css({width:0,height:0,opacity:0}).attr('src', 'fancy://things/'+thing_id).appendTo('body');
});


</script>