My friend DOM

Way back... a few months ago, when I started interviewing for coding bootcamps, one of my interviewers asked me to tell him about the DOM... and I was like, "Sorry I don't know him. Is he like to Fonz of programming..." He's not. In fact he's not a he at all.

WHAT IS "THE DOM"?
DOM is an acronym that stands for Document Object Model and it's basically a copy of the HTML that your browser renders when you open it.

WHY DO YOU NEED A COPY OF WHAT YOU WROTE?
Because it is a copy multiple users can reach out to the page without having to have the source files on their computer and they can interface with the same page at once and have a user experience that is unique from that of others.

DOM MANIPULATION:You don't want to access the DOM much. The more you grab info or push info to the DOM the slower your program will run. (because you have to wait for the script running the program to reach out to the DOM. Manipulating things in your actual script first and then sending as much correspondence to the DOM at once as you can is the preferred way to do things.

JQUERY SELECTORS AND THE DOM
Jquery makes interacting with the DOM much easier than using vanilla (plain ol') java script. The selectors allow you to easily classify and reference page elements like buttons, input and divs, text etc. The best way to learn about jQuery is to read the  jQuery docs, but the TLDR is that it is a library that has converted the long hand and sometimes confusing process of referencing the DOM with javascript into simple procedural steps. Once you add a script tag for jQuery (eg <script src="https://code.jquery.com/jquery-2.1.4.min.js"></> ) your browser will know to reference that library every time you include an $ symbol before your text. For example, $("#name") is the jQuery way to refer to an element on your DOM that has an id of name.

There are tons of handy things that can be with jQuery, so I definitely recommend having a peruse through the jQuery site.