Adding message-passing regarding shutting a checkout page down

1 files changed, 17 insertions, 1 deletions

diff --git a/api-merchant.rst b/api-merchant.rst
index 56766fc2..32bb641c 100644
--- a/api-merchant.rst
+++ b/api-merchant.rst
@@ -236,13 +236,29 @@ event.  If the Taler extension is present, it will respond with a
 
 event.  The handler should then activate the Taler payment option,
 for example by updating the DOM to enable the respective button.
-Finally, if the Taler extension is unloaded while the user is
+
+The following events are needed when one of the two parties leaves the
+scenario.
+
+First, if the Taler extension is unloaded while the user is
 visiting a checkout page, the page should listen for the
 
   .. js:data:: taler-unload
 
 event to hide the Taler payment option.
 
+Secondly, when the Taler extension is active and the user closes (or navigates
+away from) the checkout page, the page should listen to a 
+
+  .. js:data:: taler-navigating-away
+
+event, and reply with a
+
+  .. js:data:: taler-checkout-away
+
+event, in order to notify the extension that the user is leaving a checkout
+page, so that the extension can change its color back to its default.
+
 The following source code highlights the key steps for adding
 the Taler signaling to a checkout page: