Trigger "Specific Page Opened" when start chatbot

Hello,
I need to set a variable when the trigger "Specific Page Opened" is fired but the trigger is not fired when the chatbot starts and I only can set the variable from the second time I open the chatbot.

Is there a way to trigger on start?

Alternative: is there a way to pass data attribute to the widget and fill some variables?

Eg.

<script async data-id="[THE_ID_OF_THE_CHATBOT]" id="chatling-embed-script" data-some_chatbot_variable="[VALUE_FOR_THE_VARIABLE_some_chatbot_variable]" type="text/javascript" src="https://chatling.ai/js/embed.js"></script>

Thank you,
Nico.