What does the wordpress open source code allow me to do? I'm confused, many questions

Questions:

1. Since we can build a website with html/css/javascript only, why is the wordpress code useful? why do we prefer to install first and design on it? what does it allow us to do better? Answer with very specific things that it does if you can please.

2. Does maintaining/updating/securing/speeding up a website has anything to do with backend code or any code? what do I need to know to do all of this?

3. If javascript can run on the server side too and affect the database why do we even need php? is there any limitation in javascript that php covers?

4. Is backend's whole purpose to manipulate data within the database? I mean that backend skill was created in order to make web apps or more dynamic graphics? would javascript be useless without a database? when we talk about server side we basically mean the database because the database is there right? I mean nothing else matters except this

5. Is javascript so good because it can create dynamic frontend elements by affecting both the database and the frontend? can't the other backend languages do this?

6. Do I need to know php in order to create a dynamic site from scratch with wordpress? is php usefull only to create commercial themes or plugins?

1. Speed
2. Of course. It's important to keep your code up to date. Just click "Update" to update a theme or plugin most of the time.
3. Javascript only runs client side. To talk to the database you need Ajax, Php.
4. Javascript is very usefull, even without a database. You would need Ajax or Php to send changed data to the server and possibly save these in a database. Unlike Php, Ajax can change data in the database without the need to refresh the page.
5. Like said in 3, Javascript is client side.
6. No, but it helps. A lot.

Hope this helps.

JavaScript is the defacto language browsers use. WordPress is written in both PHP and JS. WordPress uses PHP to manage your data (store it in a database, use it for non-public logic, send a response, etc). Until recently, JavaScript only had browser intrerpreters. Most of the web was built before some people decided to build an interpreter for other environments like a server.

There is always a backend, even if you're serving static files. PHP (or any other server language) receives a request that tells it what the client is expecting to receive, PHP then decides what to do and sends back a response (like the HTML and JS files and very specific data the browser uses to render a page).

Should you learn PHP? If you want to become a web developer is a must. There's tons of PHP jobs (albeit lower paying compared to other languages like C), tons of docs, it's super easy and it's a very reliable language compared to JavaScript (which you will also have to learn).

1. Because it does everything for you. its a standard base on which there are thousnads of different addons, plugins that can help you do things very quickly.

2. You don't need to know any coding to use wordpress. The backend code is the code that is provided by wordpress. You just download and install it to your server. No coding needed.

3. Good question, basically PHP was being used before javascript so many server apps are still using PHP because they are old apps. Wordpress is one of these apps. One day they will switch to javascript i guess but for now they are in PHP.

4. Yes and no. the database is often the key component in any back end app. But apps can do other things as well, like proxies (which don't use any database). Graphics and javascript are separate to any database

5. javascript client side and javascript server side (node js) are separate things.

6. No you don't see question 2