JavaScript Regex Cheatsheet - Online Interactive Pattern Reference
Interactive cheatsheet for JavaScript regular expressions with live examples. Click any token to see its explanation and test it on sample text immediately.
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Quickly find, search & copy HTML symbol entities for your projects
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< displays the less-than symbol < without the browser mistaking it for an HTML tag. Using entities ensures your content renders correctly across all browsers, avoids encoding issues, and is essential for displaying reserved characters like &, <, >, and " in your HTML documents.
&) are easy to remember and read, but not every Unicode character has a named entity. Numeric codes come in two forms: decimal (&) and hexadecimal (&). Numeric codes can represent any Unicode character, making them more universal. Named entities are generally preferred for readability, while numeric codes are used when a name doesn't exist or when working with dynamic content.
<, >, &, ") to prevent parsing errors. Entities are also useful when your keyboard lacks certain symbols, when working in CMS platforms that may strip special characters, or when you need guaranteed cross-platform consistency in email HTML or legacy systems.
content: "\00A9"; for the copyright symbol ©. In JavaScript, use Unicode escape sequences like "\u00A9" or template literals with direct Unicode characters. When injecting HTML via JavaScript's innerHTML, you can use entity names like ©, but when using textContent, use the actual character or Unicode escape. For React/JSX, you can use entities directly in JSX markup or use JavaScript Unicode escapes in expressions.
(or  ) creates a space character that prevents an automatic line break at that position. Use it to keep related words together (e.g., "10 km"), in table cells that shouldn't collapse, or to create indentation. However, avoid using multiple for layout spacing — use CSS margins and padding instead. Overusing can create accessibility issues for screen readers and make responsive design harder to manage.
| Symbol | Entity Name | Decimal | Hex | Description |
|---|---|---|---|---|
| & | & | & | & | Ampersand |
| < | < | < | < | Less than |
| > | > | > | > | Greater than |
| " | " | " | " | Double quote |
| ' | ' | ' | ' | Single quote |
| © | © | © | © | Copyright |
| ® | ® | ® | ® | Registered trademark |
| € | € | € | € | Euro currency |
| — | — | — | — | Em dash |
|   |   | Non-breaking space |
Interactive cheatsheet for JavaScript regular expressions with live examples. Click any token to see its explanation and test it on sample text immediately.
Select emojis and arrange them into a seamless tiling background. Copy the CSS data‑URI or download as image.
Search and filter all CSS properties that can be animated. See value types and example keyframes. Quick dev reference.
Create and format Markdown tables by adjusting rows and columns. Align text, copy the raw Markdown. Perfect for README files.
Quick reference of HTTP methods with their semantics, idempotency, and example REST usage. Static, fast.
Generate an SVG placeholder image with custom text, width, height, and colors. Use as a placeholder service. Pure SVG.
Enter a common chemical name to see summary hazard pictograms and precautions. Quick reference.
Generate the doGet() and doPost() boilerplate for a Google Apps Script web app. Ready to paste into the editor.
Drag and drop pieces to set up a chess position. Generate FEN string and copy to share. Analyze openings. Local only.
Search for common ingredient substitutions (e.g., buttermilk, egg, cornstarch). Quick reference for when you're missing something. Local data.
Convert a small image into a Base64 data URI and get a Markdown image tag. Perfect for README files and note‑taking apps. Local.
Search for the NaOH and KOH sap values of various oils. Reference for cold process soap makers.
Create a Blob from text or a file and generate a temporary URL for it. Understand the Blob API. Dev demo.
Choose Babel presets (env, React, TypeScript) and plugins. Get a clean babel.config.json to transpile your code. Local tool.
Select a Node.js version from the LTS list and instantly download a .nvmrc file. Lock your project’s runtime.
Overlay outlines of different paper sizes scaled to real dimensions on screen. Choose the right one.
Generate strong random strings for API tokens, session secrets, or encryption keys. Uses crypto.getRandomValues().
Stack multiple background images and blend them with colors. Create unique textures. Copy the CSS code instantly.
Choose the right extinguisher for kitchen, electrical, or garage fires. Interactive class chart. Home safety education.
Create a reflection effect for images or text using box‑reflect. Adjust direction and offset. Copy the CSS.
Sortable list of cooking oils with smoke points and best uses. Choose the right fat for the right heat.
Recreate the target CSS linear gradient by adjusting stops and colors. A unique game for front‑end developers to master gradients.
Paste raw email headers and get a human-readable breakdown of the delivery route, authentication results, and delays. Private analysis.
Create CSS animations and transitions without coding. Define keyframes, easing, and duration. Copy the @keyframes and animation code instantly.
Virtual paper fortune teller. Pick a color, count, and reveal a random fortune. Nostalgic fun.
Enter your bow's draw weight, arrow length, and point weight to find the correct arrow spine. Essential for tuning.
See how `animation‑composition: replace, add, accumulate` works by layering animations on the same property. Understand the spec.
Select text and see the Selection object properties. Create ranges programmatically. Understand how rich‑text editors work.
Easily compute posterior probabilities given prior, likelihood, and marginal likelihood. Visual diagram. All local.
Adjust rotateX/Y/Z and translate to see a 3D box in real time. Copy optimized CSS transform.