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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
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Advanced HTML Tags Reference
// obscure · semantic · powerful · browser-native
TagRarityPurposeKey Attributes
<details>RareNative collapsible/accordion widgetopen
<summary>RareVisible label inside <details>
<dialog>EpicNative modal/popup dialogopen, JS: .showModal()
<datalist>RareAutocomplete suggestions for inputsid
<output>EpicDisplays result of a calculationfor, name
<meter>RareScalar measurement within a rangemin, max, value, low, high, optimum
<progress>RareProgress indicator / loading barvalue, max
<template>EpicInert HTML fragment for JS cloningid
<slot>LegendWeb Components content placeholdername
<picture>RareResponsive image with source conditions
<source>RareConditional media sourcesrcset, media, type
<map> + <area>EpicClickable image map regionsname, shape, coords, href
<ruby>EpicRuby annotations (Asian typography)
<rt>EpicRuby text (pronunciation above base)
<rp>EpicRuby parenthesis fallback
<wbr>RareWord break opportunity hint
<bdi>LegendBidirectional text isolation
<bdo>EpicOverride text directiondir (ltr/rtl)
<object>EpicEmbed external resource (SVG, PDF, etc.)data, type, width, height
<param>LegendParameter for <object>name, value
<col> + <colgroup>EpicStyle entire table columnsspan
<fieldset>RareGroup form controls with borderdisabled, name
<legend>RareCaption for <fieldset>
<time>RareMachine-readable date/timedatetime
<kbd>RareKeyboard input representation
<samp>EpicSample computer output
<var>RareMathematical / programming variable
<ins> / <del>RareInserted / deleted content (track changes)datetime, cite
<cite>RareReference to a creative work
<dfn>RareDefinition of a termtitle