// Learn
// Try It
// Reference
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The hidden tags await
This is the second volume. We go deeper — tags that browsers support but developers forget, ignore, or never discovered.
HTML
CSS
JS
Preview
sandbox://preview
Advanced HTML Tags Reference
// obscure · semantic · powerful · browser-native
| Tag | Rarity | Purpose | Key Attributes |
|---|---|---|---|
<details> | Rare | Native collapsible/accordion widget | open |
<summary> | Rare | Visible label inside <details> | — |
<dialog> | Epic | Native modal/popup dialog | open, JS: .showModal() |
<datalist> | Rare | Autocomplete suggestions for inputs | id |
<output> | Epic | Displays result of a calculation | for, name |
<meter> | Rare | Scalar measurement within a range | min, max, value, low, high, optimum |
<progress> | Rare | Progress indicator / loading bar | value, max |
<template> | Epic | Inert HTML fragment for JS cloning | id |
<slot> | Legend | Web Components content placeholder | name |
<picture> | Rare | Responsive image with source conditions | — |
<source> | Rare | Conditional media source | srcset, media, type |
<map> + <area> | Epic | Clickable image map regions | name, shape, coords, href |
<ruby> | Epic | Ruby annotations (Asian typography) | — |
<rt> | Epic | Ruby text (pronunciation above base) | — |
<rp> | Epic | Ruby parenthesis fallback | — |
<wbr> | Rare | Word break opportunity hint | — |
<bdi> | Legend | Bidirectional text isolation | — |
<bdo> | Epic | Override text direction | dir (ltr/rtl) |
<object> | Epic | Embed external resource (SVG, PDF, etc.) | data, type, width, height |
<param> | Legend | Parameter for <object> | name, value |
<col> + <colgroup> | Epic | Style entire table columns | span |
<fieldset> | Rare | Group form controls with border | disabled, name |
<legend> | Rare | Caption for <fieldset> | — |
<time> | Rare | Machine-readable date/time | datetime |
<kbd> | Rare | Keyboard input representation | — |
<samp> | Epic | Sample computer output | — |
<var> | Rare | Mathematical / programming variable | — |
<ins> / <del> | Rare | Inserted / deleted content (track changes) | datetime, cite |
<cite> | Rare | Reference to a creative work | — |
<dfn> | Rare | Definition of a term | title |