Issues

• [p~="a b"] matches although the value contains whitespace

  bug
  capricorn86/happy-dom#2508 · Filter by author robertmorelli opened on Oct 12, 2026

• pseudo-class between two functional pseudo-classes is ignored

  bug
  capricorn86/happy-dom#2507 · Filter by author robertmorelli opened on Oct 12, 2026

• attribute selectors with an empty value: ^= $= ~= match, |= misses "-x"

  bug
  capricorn86/happy-dom#2506 · Filter by author robertmorelli opened on Oct 12, 2026

• subsequent-sibling combinator (~) stops at the first match

  bug
  capricorn86/happy-dom#2505 · Filter by author robertmorelli opened on Oct 12, 2026

• Support the CSS Custom Highlight API (Highlight, HighlightRegistry, CSS.highlights)

  enhancement
  capricorn86/happy-dom#2501 · Filter by author NullVoxPopuli opened on Oct 11, 2026

• matches() and getComputedStyle() keep a stale :has() result after a descendant changes

  capricorn86/happy-dom#2499 · Filter by author asavis opened on Oct 11, 2026

• select fires synchronously from setSelectionRange(), and getModifierState('AltGraph') returns altKey

  capricorn86/happy-dom#2495 · Filter by author asavis opened on Oct 11, 2026

• document.cookie: a cookie set with Max-Age=0 is not deleted

  capricorn86/happy-dom#2494 · Filter by author asavis opened on Oct 11, 2026

• Storage methods are bound onto the store on first use, and a method defined on the store cannot be deleted

  capricorn86/happy-dom#2493 · Filter by author asavis opened on Oct 11, 2026

• Missing or misplaced DOM API surface: tbody/thead rows, Request.keepalive, window.DOMTokenList, client* on Element, getClientRects() of display: none

  capricorn86/happy-dom#2492 · Filter by author asavis opened on Oct 11, 2026

• querySelectorAll() rejects an escaped quote inside a quoted attribute value

  capricorn86/happy-dom#2491 · Filter by author asavis opened on Oct 11, 2026

• CSSStyleDeclaration rejects min(), max(), clamp(), round() and container units, keeps colours as written, and keeps '0' for logical properties

  capricorn86/happy-dom#2490 · Filter by author asavis opened on Oct 11, 2026

• matches() and getComputedStyle() still keep a stale result after an ancestor above the parent changes (follow-up to #2442)

  capricorn86/happy-dom#2489 · Filter by author asavis opened on Oct 11, 2026

• getComputedStyle() returns '' for properties nothing sets and for inherited custom properties

  capricorn86/happy-dom#2488 · Filter by author asavis opened on Oct 11, 2026

• Label activation clicks the control for a click on other interactive content in the label, and before the click has finished dispatching

  capricorn86/happy-dom#2487 · Filter by author asavis opened on Oct 11, 2026

• focus() moves focus to elements that are not focusable areas, and an element disabled while focused never blurs

  capricorn86/happy-dom#2486 · Filter by author asavis opened on Oct 11, 2026

• navigator.sendBeacon() leaves its fetch() promise unhandled, so a failed beacon becomes an unhandled rejection

  bug
  capricorn86/happy-dom#2485 · Filter by author asavis opened on Oct 10, 2026

• input[type=number]: an empty min, max or step attribute is read as 0, so validity reports rangeOverflow / rangeUnderflow / stepMismatch

  bug
  capricorn86/happy-dom#2484 · Filter by author asavis opened on Oct 10, 2026

• XMLHttpRequest drops the DELETE request body (no Content-Length, no chunked encoding)

  capricorn86/happy-dom#2480 · Filter by author drakulavich opened on Oct 9, 2026

• history.replaceState causes hashchange to be fired

  bug
  capricorn86/happy-dom#2479 · Filter by author t3chguy opened on Oct 9, 2026

• Element.toString() returns outerHTML instead of "[object HTMLDivElement]"

  bug
  capricorn86/happy-dom#2478 · Filter by author caillou opened on Oct 9, 2026
  2

• WritableStream and TransformStream are Node's classic stream.Writable/stream.Transform, not the WHATWG classes

  capricorn86/happy-dom#2474 · Filter by author jakeleventhal opened on Oct 6, 2026

• XMLHttpRequest drops Content-Length from request bodies

  capricorn86/happy-dom#2472 · Filter by author josegonzalez opened on Oct 6, 2026

• validity.stepMismatch is true for almost every value with a decimal step (step="0.01"), so the form never submits

  capricorn86/happy-dom#2471 · Filter by author Luzivog opened on Oct 6, 2026

• labels includes an ancestor <label> whose labeled control is a different element

  capricorn86/happy-dom#2470 · Filter by author Luzivog opened on Oct 6, 2026