:has() CSS relational pseudo-class

Select elements containing specific content. For example, `a:has(img)` selects all `<a>` elements that contain an `<img>` child.

Hashchange event

Event triggered in JavaScript when the URL's hash has changed (for example: page.html#foo to page.html#bar)

text-emphasis styling

Method of using small symbols next to each glyph to emphasize a run of text, commonly used in East Asian languages. The `text-emphasis` shorthand, and its `text-emphasis-style` and `text-emphasis-color` longhands, can be used to apply marks to the text. The `text-emphasis-position` property, which inherits separately, allows setting the emphasis marks' position with respect to the text.

audioparammap api: has

cachestorage api: has

customstateset api: has

document api: hasfocus

document api: hasprivatetoken

document api: hasredemptionrecord

document api: hasstorageaccess

domimplementation api: hasfeature

element api: hasattribute

element api: hasattributens

element api: hasattributes

element api: haspointercapture

eventcounts api: has

fontfaceset api: has

formdata api: has

gamepadpose api: hasorientation

gamepadpose api: hasposition

hashchangeevent api

hashchangeevent api: newurl

hashchangeevent api: oldurl

headers api: has

highlightregistry api: has

highlight api: has

htmlanchorelement api: hash

htmlareaelement api: hash

keyboardlayoutmap api: has

location api: hash

mediakeystatusmap api: has

midiinputmap api: has

midioutputmap api: has

navigateevent api: hashchange

navigateevent api: hasuavisualtransition

node api: haschildnodes

popstateevent api: hasuavisualtransition

pushmanager api: haspermission

rtcstatsreport api: has

sensor api: hasreading

urlpattern api: hash

urlpattern api: hasregexpgroups

urlsearchparams api: has

urlsearchparams api: has: `value` parameter

url api: hash

useractivation api: hasbeenactive

workerlocation api: hash

xranchorset api: has

javascript built-in: map: has

grammar: hashbang (`#!`) comment syntax