This is a list of helpful programming resources.

1. ($) means this site has a priced option.

1 Javascript

1.1 Test Javascript, HTML, CSS online

1. Codepen. They call a new project a "pen". This has panes for HTML, CSS and JavaScript. https://codepen.io/your-work
2. Google Colab. This supports Javascript by putting %%javascript or %%js at the top of a cell. I believe this requires you to login via a free Google account. https://colab.research.google.com/
3. Javascript Playground. Run JS online.There is a popup that will not go away so the site is unusable. https://playcode.io/javascript-playground
4. JS.do. Has HTML pane, where you must put JS, but no other panes. Has login option. Code pane does not wrap to pane size. https://js.do/
5. JSBin. Cick on a button to change panes for HTML, CSS, Javascript, the console, or output. Has login feature to save your tests. https://jsbin.com
6. JSFiddle. Share examples, collaborate with other users. It has an option to login to keep your test cases. https://jsfiddle.net/
7. Visual Studio Code. When people are testing Javascript with HTML, they often use Microsoft's VSC and an extension called Live Server. VSC also supports various AI components to help you code. https://code.visualstudio.com/download Live Server by Ritwick Dey: https://marketplace.visualstudio.com/items?itemName=ritwickdey.LiveServer You can also install Live Server by searching for it in VSC.
8. Web Toolkit JavaScript Tester. No sign in needed. This has various convertors like hex, CSV to XML, encoders like Base64 or URL, formatters for CSS, JSON, SQL, XML, HTML, etc. It also has a regular expression tester. https://www.webtoolkitonline.com/javascript-tester.html

1.2 Test JS with local install

1. Jest. It works with projects using: Babel, TypeScript, Node, React, Angular, Vue and more! https://jestjs.io/
2. RunJS. This is something you must download. https://runjs.app/play

1.3 Online JS compilers

1. OneCompiler. There is no pane for HTML or CSS, just for JS. They support about 50+ languages here including Basic, C, C++, C#, Python. https://onecompiler.com/javascript
2. Playcode JS Compiler. "Run JavaScript online with TypeScript, JSX, and npm support. Compile JS code instantly in your browser. Free, no signup required." Start from scracth or use one of their templates or use AI to describe what you want. Create a website or code. https://playcode.io/javascript-compiler

1.4 Tools

1. Playcode. ($) Build apps and sites with AI. There is a sign in option. They have more compilers online like Go, SQL. This site has a popup where you choose the language to support but it doesn't go away making it impossible to use the site for Javascript. https://playcode.io
   1. C compiler. https://playcode.io/c-compiler
   2. C++ compiler. https://playcode.io/cpp-compiler
   3. Python. https://playcode.io/python-compiler
   4. Typescript. Test TS here. https://playcode.io/typescript

1.5 Tutorials/Education

1. Testing JavaScript. Teaches you how to test JS. https://www.testingjavascript.com/

1.6 JS Code Examples

1.6.1 Print JS version

This will print the interpreter type, like "Node" and the version.

//This is a comment, but this comment style not supported for all JS clients.
console.log("Running JS: " + navigator.userAgent)

1.7 HTML

1.7.1 Hiding text

Browsers may vary in which method they support. <div style="display:none;"></div> takes up no space in the document.

//Use the 'hidden' attribute in HTML.
<P>This is a paragraph which you should see.</p>
<p hidden>This is hidden.</p>
<div hidden>
  This div is hidden.
  </div>
<p>You should see this text below the hidden div.</p>