A Step-by-Step Example of using an HTML Form to send a "Contact Us" Message via Email without a Backend Server using a Google Script - No PHP, Python, Ruby, Java, Node.js etc.
See a working example here: https://dwyl.github.io/html-form-send-email-via-google-script-without-server/
Warning: Google's API has limits on how many emails it can send in a day. This may vary on your Google account, see the limits here. We recommend implementing this tutorial through Part 3, since the data will always be added to the spreadsheet first, then emailed if possible.