store navigator.appName in session object on init

functions.php

@@ -2742,6 +2742,8 @@
 
 			}
 
+			print '[' . $_SESSION["client.userAgent"] . ']';
+
 			print "<td class=\"headlineActions$rtl_cpart\">
 				<ul class=\"headlineDropdownMenu\">
 				<li class=\"top2\">

modules/backend-rpc.php

@@ -185,6 +185,10 @@
 				print "<error error-code=\"0\"/>";
 				print_init_params($link);
 				print_runtime_info($link);
+
+				# assign client-passed params to session
+				$_SESSION["client.userAgent"] = $_GET["ua"];
+
 			}
 			print "</rpc-reply>";
 		}		

tt-rss.js

@@ -364,7 +364,9 @@ function init() {
 			debug('debug mode activated');
 		}
 
-		xmlhttp.open("GET", "backend.php?op=rpc&subop=sanityCheck", true);
+		var params = "&ua=" + param_escape(navigator.userAgent);
+
+		xmlhttp.open("GET", "backend.php?op=rpc&subop=sanityCheck" + params, true);
 		xmlhttp.onreadystatechange=backend_sanity_check_callback;
 		xmlhttp.send(null);