diff --git a/Abfall_ICS/form.json b/Abfall_ICS/form.json
index 576c393..a3917e5 100644
--- a/Abfall_ICS/form.json
+++ b/Abfall_ICS/form.json
@@ -79,7 +79,7 @@
                             "name": "clientURL",
                             "caption": "Download URL (iCal-File):",
                             "width": "900px",
-                            "validate": "^(http(s?):\\/\\/)?(((www\\.)?[a-zA-Z0-9\\.\\-\\_]+(\\.[a-zA-Z]{2,3})+)(:[0-9]{1,5})?|(\\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\b))(:[0-9]{1,5})?(\\/[a-zA-Z0-9\\_\\-\\s\\.\\/\\?\\%\\#\\&\\=]*)?$"
+                            "validate": "^(http(s?):\\\/\\\/)?(((www\\.)?[a-zA-Z0-9\\.\\-\\_]+(\\.[a-zA-Z]{2,3})+)(:[0-9]{1,5})?|(\\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\b))(:[0-9]{1,5})?(\\\/[a-zA-Z0-9\\_\\-\\s\\,\\.\\\/\\?\\%\\#\\&\\=]*)?$"
                         }
                     ]
                 },