Hidden Features

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CSS Advanced

mix-blend-mode: Text That Recolors Itself Against Any Background

A fixed header readable over every hero image, duotone photos without Photoshop, highlight effects that multiply like a real marker - blend modes, and the isolation property that keeps them caged.

Sep 20, 2025 2 min 645 Read →

C

CSS Intermediate

color-mix(): Hover States Without a Second Color Definition

Darker-on-hover, tinted backgrounds, borders derived from the brand color - color-mix computes them in the browser from one source color, and your theme stops needing a palette generator.

Sep 10, 2025 2 min 688 Read →

C

CSS Beginner

CSS Nesting Is Native Now - Here's What Sass Habits to Keep and Drop

The browser parses nested CSS without any build step. The syntax is almost Sass - the differences, the & rules, and the over-nesting trap are what matter.

Aug 11, 2025 2 min 1,381 Read →

C

CSS Intermediate

Container Queries: Components That Fit Their Container, Not the Screen

A card in a sidebar and the same card full-width need different layouts - media queries cannot tell them apart. Container queries finally let components respond to their own space.

Jul 28, 2025 2 min 1,787 Read →

W

JavaScript Advanced

Why "👨‍👩‍👧".length Is 8, and How to Count What Users See

String length counts UTF-16 code units, not characters - so emoji truncation splits families into corpses. Intl.Segmenter counts graphemes, words and sentences correctly.

Jun 23, 2025 2 min 1,238 Read →

J

JavaScript Intermediate

JSON.stringify Takes Two More Arguments Than You Think

The replacer filters and redacts on the way out, the reviver rebuilds Dates on the way in, and toJSON lets objects decide their own serialization. All native, all ignored.

Jun 3, 2025 2 min 1,680 Read →

I

DOM Intermediate

inert: Disable an Entire Section of the Page in One Attribute

While a modal is open, the page behind it should not be clickable, tabbable or readable by screen readers. inert does all three - focus traps become one line.

May 24, 2025 2 min 1,694 Read →

T

CSS Intermediate

The popover Attribute: Dropdowns Without the JavaScript

Toggle behavior, light dismiss, Escape handling, top-layer rendering - the popover attribute gives you all of it declaratively. Menus and tooltips just got dramatically simpler.

May 15, 2025 2 min 1,773 Read →

T

JavaScript Intermediate

The Form Validation API You Already Shipped

required, pattern and type attributes feed a full JavaScript API: custom error messages, on-your-terms timing, and async checks - without a validation library.

May 9, 2025 2 min 1,757 Read →

L

JavaScript Intermediate

Lazy Sequences with Generators: Compute Only What You Use

Generators pause between values, which makes infinite sequences, cheap ID factories and stop-early pipelines natural - no arrays, no wasted work.

Feb 13, 2025 1 min 3,115 Read →

M

JavaScript Advanced

Make Any Object Spreadable: Symbol.iterator in Practice

for...of, spread, destructuring and Array.from all speak one protocol. Implement one method and your own classes join Map, Set and NodeList as first-class iterables.

Feb 9, 2025 2 min 1,581 Read →

A

JavaScript Advanced

A 15-Line Proxy That Tells You Exactly What Changed

Dirty checking, undo history, "unsaved changes" warnings - all reduce to knowing when an object changed. Proxy intercepts the writes themselves, no framework needed.

Feb 1, 2025 2 min 1,666 Read →