diff --git a/scripts/abfahrtsmonitor.py b/scripts/abfahrtsmonitor.py
index 6de6ace..edf72b8 100644
--- a/scripts/abfahrtsmonitor.py
+++ b/scripts/abfahrtsmonitor.py
@@ -10,42 +10,35 @@ import urllib2
 form = cgi.FieldStorage()
 
 url = "http://widgets.vvo-online.de/abfahrtsmonitor/"
-querytype = ""
-ort = ""
-hst = ""
-vz = ""
-vm = ""
-timestamp = ""
+query = ""
+
+queries = {
+    "ort": "",
+    "hst": "",
+    "vz": "",
+    "vm": "",
+    "timestamp": ""
+}
+
+# available server scripts = valid queries
+validqueries = ["haltestelle.do", "abfahrten.do"]
 
 # check for queries
 if (form.getvalue('query')):
     query = form.getvalue('query')
-if (form.getvalue('ort')):
-    ort = form.getvalue('ort')
-if (form.getvalue('hst')):
-    hst = form.getvalue('hst')
-if (form.getvalue('vz')):
-    vz = form.getvalue('vz')
-if (form.getvalue('vm')):
-    vm = form.getvalue('vm')
-if (form.getvalue('timestamp')):
-    timestamp = form.getvalue('timestamp')
 
-validqueries = ["haltestelle.do", "abfahrten.do"]
-
-queries = {
-    "ort": ort,
-    "hst": hst,
-    "vz": vz,
-    "vm": vm,
-    "timestamp": timestamp
-}
+for key in queries.viewkeys():
+    if (form.getvalue(key)):
+        queries[key] = form.getvalue(key)
 
+# call the vvo server if the query is valid
 if (query in validqueries):
     url += query + "?" + urllib.urlencode(queries)
     data = urllib2.urlopen(url).read()
 else:
     data = "[]"
 
+# return the http response with the data received from server
+# or an empty array if query was invalid
 print("Content-type: text/html\n\n")
 print(data)