Web Development

A growing collection of web-development references — practical, example-driven documentation on the core technologies of the web.

Sections

  • What is CORS? — what Cross-Origin Resource Sharing is, how the browser and server negotiate it, and how to validate origins correctly on the backend.

  • Web Accessibility — what web accessibility is, the WCAG A/AA/AAA conformance levels, legal accessibility standards in Spain, Europe, and the USA, and validation tools.

  • HTML & CSS Reference — structure, layout, styling, forms, and performance, covering modern HTML5 and CSS from the ground up, plus a downloadable cheat sheet.

  • Sass Reference — the SASS/SCSS CSS preprocessor: syntax, variables, nesting, mixins, functions, and modules, plus a downloadable cheat sheet.

  • JavaScript Development — modern ECMAScript, core browser APIs, and the surrounding developer-tooling ecosystem, plus a downloadable cheat sheet.

  • Bootstrap Reference — the Bootstrap 5 CSS/JS framework: the grid system, components, utilities and the Utility API, customization, and JavaScript behavior, plus a downloadable cheat sheet.

  • jQuery Reference — DOM traversal/manipulation, events, effects, and AJAX with jQuery 3.x, when to prefer native APIs, plus a downloadable cheat sheet and a self-test questionnaire with verified answers.

  • React Reference — components and Hooks, state, effects, Suspense, forms and Actions, data fetching, SSR/SSG/RSC, and build and deployment with React 19, plus a downloadable cheat sheet.

  • Angular Reference — components and templates, signals, the built-in control flow and @defer, dependency injection, RxJS, the HTTP client, routing, forms, testing, and SSR and performance with modern standalone Angular, plus a downloadable cheat sheet.

  • ASP.NET Reference — three lineages, each in its own sub-section: ASP.NET Web Forms (postbacks, ViewState, server controls, on .NET Framework 4.8.1), ASP.NET MVC (Razor) (MVC 5, Web API 2, OWIN, Identity 2, also on .NET Framework 4.8.1), and ASP.NET Core (Blazor) (the minimal hosting model, middleware, Minimal APIs, MVC & Razor Pages, the Blazor cluster, SignalR & gRPC, EF Core, authentication & authorization, and deployment on .NET 10) — plus a history of how they relate, a framework decision guide, and three downloadable cheat sheets.

  • Tailwind Reference — the utility-first CSS framework: the utility-first workflow, states and variants, responsive design and container queries, dark mode, theme variables and the OKLCH palette, Preflight, the utility families, CSS-first customization with @theme / @utility / @custom-variant, arbitrary values, build and production, and a v3-to-v4 upgrade guide for Tailwind CSS v4, plus a downloadable cheat sheet.

  • TypeScript Reference — the typed superset of JavaScript: the type system and structural typing, unions and narrowing, interfaces, generics and type-level programming, the utility types, satisfies and assertions, modules and declaration files, tsconfig and the compiler, decorators, and JavaScript interop and migration, plus a downloadable cheat sheet.

  • Vue.js Reference — the progressive framework: reactivity and the Composition API with <script setup>, template syntax and directives, components (props, events, v-model, slots, provide/inject), composables, the built-in components and transitions, single-file components and tooling, Vue Router, Pinia, testing, SSR, and Vue with TypeScript, plus a downloadable cheat sheet.

  • Vaadin Reference — the server-driven Java web framework: Flow (Java UI) and Hilla (React + type-safe endpoints), the component set and layouts, Binder data binding, the Grid, routing, server push, the Element API, Lumo/Aura theming, Spring Boot and Jakarta EE integration, security, testing, and production deployment, plus a UI component libraries survey and a downloadable cheat sheet.

  • Python Reference — the Python language itself: core types and control flow, functions and scope, OOP and decorators, modern features — type hints, dataclasses, asyncio — the standard library, and unit testing with pytest and mocking, plus a downloadable cheat sheet.