How to assign javascript variable value to slots


I have a form which sends user details such as name, email, and phone number before starting the conversation. This is done with the help of html, css, js, and jquery. Is there a way by which I can store the value which the user types in the email field of the form to a rasa slot named ‘email’ rather than asking the user to type the email once again?

Any help will be highly appreciated.