fixed hanging infocard when position doesn't exist

fix #58

Author: rossengeorgiev

js/tracker.js

@@ -1182,13 +1182,14 @@ var mapInfoBox_handle_path = function(event) {
 
 var mapInfoBox_handle_path_fetch = function(id,vehicle) {
     $.getJSON("http://spacenear.us/tracker/datanew.php?mode=single&format=json&position_id=" + id, function(data) {
-        data = data.positions.position[0];
-
-        if(data.length === 0) {
-            box.setContent("unable to find data");
+        if('positions' in data && data.positions.position.length === 0) {
+            mapInfoBox.setContent("not found");
+            mapInfoBox.open(map);
             return;
         }
 
+        data = data.positions.position[0];
+
         div = document.createElement('div');
 
         html = "<div style='line-height:16px'>";