Confusion about how Front end code connects to backend

Hello community. I’ve had a question that I can’t seem to find an answer online. I’ve learned the basics on creating a page using HTML & CSS. How do I know the website is ready or correctly coded to pass it to a backend developer. An example of what I’m talking about is, if I have a page that has a “enter your email” input and some other information, do I have to add any extra coding so that backend can take that email and send it somewhere or do they modify the code in order to get the value and save it somewhere? I can create a page but I’m not sure I understand how it will connect to back end. Thanks!

For the simplest web pages that use a form and set the action attribute to a URL that can process the information sent by the form:

<form action="/some_url_that_can_process_the_form_data">

then technically you don’t need to do anything special other than make sure your HTML is valid, and the script waiting at that URL will do all of the processing of the data for you.

But realistically, most web pages do pre-processing of the data before sending the data on to the server and that’s where JS comes in. As to how you use JS to pass data to the backend, that’s usually done through an API that allows you to communicate with the backend.

Thank you very much for the clarification! I’m still working my way through JS but now I feel more confident about finishing a page and sharing the code. Thanks!