Open Source & Free Tools for Web Workers

Regulex, is a JavaScript Regular Expression Parser & Visualizer. It is designed to parse and visualize regular expressions.

Key features:

• It is written in pure JavaScript, so no backend is required.

• The visualization can be embedded on a user's site using an HTML iframe.

• It provides detailed error messages, often pinpointing the exact location of a syntax error.

• Regulex does not support octal escapes. According to the source, this is intentional, because ECMAScript strict mode does not allow octal escapes in strings. Regulex will treat DecimalEscapes as back references and throw an error if they are invalid or appear in a character set.

Regulex also has an API that allows users to parse a regular expression into an Abstract Syntax Tree (AST) and to visualize it using Raphael. The API includes functions to parse regular expressions, visualize them, and log errors.

The application can be installed using npm for Node.js. It also provides instructions for local browser builds.

CSS-Selectors describes CSS selectors, which are patterns used to select and style HTML elements. It serves as a visual guide and reference to these selectors.

Here's a summary of its main points:

• CSS selectors are used to apply styles to specific HTML elements.

• The guide covers traditional CSS selectors, pseudo-classes, and pseudo-elements.

• Pseudo-classes style elements based on their state or relation to other elements and start with a single colon (:), like :hover.

• Pseudo-elements style specific parts of an element and start with double colons (::), such as ::before.

• The guide lists various selectors such as universal (*), element, class (.class), ID (#id), and combinations of classes and IDs.

• It explains combinators like comma (,), descendant (space), adjacent (+), child (>), and general sibling (~) selectors.

• The guide also covers attribute selectors that target elements with specific attributes or attribute values using brackets [].

• It lists pseudo-classes for links (:link, :visited, :hover, :active), input focus (:focus), checked inputs (:checked), enabled or disabled inputs (:disabled, :enabled), valid or invalid inputs (:valid, :invalid), required or optional inputs (:required, :optional), and more.

• The guide provides pseudo-classes for selecting elements based on their position within a parent: first child (:first-child), last child (:last-child), nth child (:nth-child), nth-last-child (:nth-last-child), only child (:only-child), first of type (:first-of-type), last of type (:last-of-type), nth-of-type (:nth-of-type), nth-last-of-type (:nth-last-of-type), and only of type (:only-of-type).

• It includes the :target pseudo-class for selecting elements with an ID that matches the URL fragment.

• The guide also describes functional pseudo-classes like :not() for excluding elements and :has() for styling an element based on its contents.

• It covers pseudo-elements to insert content before (::before) or after (::after) an element, style the first letter (::first-letter) or line (::first-line), style input placeholders (::placeholder), selection (::selection), and list markers (::marker).

• Additional pseudo-classes are also mentioned including :root, :is(), :where(), :default, :empty, :fullscreen, :in-range, :out-of-range, :indeterminate, :read-only, :read-write and :lang().

• The document also lists various SVG generators, tools and design resources.

In short, this document is a comprehensive guide to CSS selectors, which are essential for styling web pages.