Option to control if pages with no renderable content are a change (example: JS webapps that dont render any text sometimes) (#608)

changedetectionio/model/App.py

@@ -30,6 +30,7 @@ class model(dict):
                     'password': False,
                     'base_url' : None,
                     'extract_title_as_title': False,
+                    'empty_pages_are_a_change': False,
                     'fetch_backend': os.getenv("DEFAULT_FETCH_BACKEND", "html_requests"),
                     'global_ignore_text': [], # List of text to ignore when calculating the comparison checksum
                     'global_subtractive_selectors': [],