Dependent Dropdown menus

Hi everyone I'm fairly new and unfamiliar with JavaScript/Web Dev and I'm trying to make two dropdown menus, where the second menu changes depending on what they choose on the first one

for example

Choice1
Choice2
Choice3

and if they choose Choice1 the next drop down might be

Choice1.1
Choice1.2

and a follow up question would be, how can I get what the User chose? This also does not have to be written in javascript. Any help/resources/readings would be very helpful (I've tried doing google searches but I couldn't find anything) Thank you!