Can I use…

CSS

#rrggbbaa hex color notation ::first-letter CSS pseudo-element selector ::placeholder CSS pseudo-element ::selection CSS pseudo-element :default CSS pseudo-class :dir() CSS pseudo-class :focus-within CSS pseudo-class :has() CSS relational pseudo-class :in-range and :out-of-range CSS pseudo-classes :indeterminate CSS pseudo-class :matches() CSS pseudo-class :optional CSS pseudo-class :placeholder-shown CSS pseudo-class Blending of HTML/SVG elements CSS @apply rule CSS Appearance CSS Canvas Drawings CSS Containment CSS Cross-Fade Function CSS Device Adaptation CSS Exclusions Level 1 CSS Grid Layout CSS Initial Letter CSS Masks CSS Motion Path CSS Reflections CSS Scroll snap points CSS all property CSS background-attachment CSS background-blend-mode CSS currentColor value CSS display: contents CSS font-rendering controls CSS font-size-adjust CSS font-stretch CSS hanging-punctuation CSS image-set CSS initial value CSS line-clamp CSS namespaces CSS page-break properties CSS position:fixed CSS position:sticky CSS revert value CSS scrollbar styling CSS text-indent CSS text-justify CSS text-orientation CSS text-stroke and text-fill CSS touch-action property CSS unset value CSS user-select: none CSS widows & orphans CSS will-change property CSS writing-mode property CSS zoom CSS3 attr() function CSSOM Scroll-behavior Case-insensitive CSS attribute selectors Explicit descendant combinator >> Improved kerning pairs & ligatures Media Queries: interaction media features Rebeccapurple color background-position-x & background-position-y letter-spacing CSS property selector list argument of :not() selector list argument of :nth-child and :nth-last-child CSS pseudo-classes

CSS2

CSS3

@font-face Web fonts CSS ::marker pseudo-element CSS Animation CSS Backdrop Filter CSS Counter Styles CSS Feature Queries CSS Filter Effects CSS Generated content for pseudo-elements CSS Gradients CSS Hyphenation CSS Logical Properties CSS Regions CSS Repeating Gradients CSS Shapes Level 1 CSS Variables (Custom Properties) CSS background-position edge offsets CSS background-repeat round and space CSS box-decoration-break CSS clip-path property (for HTML) CSS element() function CSS filter() function CSS first-line pseudo-element CSS font-feature-settings CSS font-smooth CSS font-variant-alternates CSS outline properties CSS overflow-anchor (Scroll Anchoring) CSS pointer-events (for HTML) CSS resize property CSS text-size-adjust CSS3 2D Transforms CSS3 3D Transforms CSS3 Background-image options CSS3 Border images CSS3 Border-radius (rounded corners) CSS3 Box-shadow CSS3 Box-sizing CSS3 Colors CSS3 Cursors (original values) CSS3 Cursors: zoom-in & zoom-out CSS3 Media Queries CSS3 Multiple backgrounds CSS3 Multiple column layout CSS3 Opacity CSS3 Overflow-wrap CSS3 Text-overflow CSS3 Text-shadow CSS3 Transitions CSS3 font-kerning CSS3 image-orientation CSS3 object-fit/object-position CSS3 selectors CSS3 tab-size CSS3 text-align-last CSS3 word-break Crisp edges/pixelated images Flexible Box Layout Module Font unicode-range subsetting Intrinsic & Extrinsic Sizing Media Queries: resolution feature TTF/OTF - TrueType and OpenType font support Viewport units: vw, vh, vmin, vmax calc() as CSS unit value ch (character) unit rem (root em) units text-decoration styling text-emphasis styling

Canvas

HTML5

Attributes for form submission Audio Tracks Audio element Autofocus attribute Canvas (basic support) Color input type Custom Elements v0 Custom Elements v1 Custom protocol handling Datalist element Date and time input types Details & Summary elements Dialog element Download attribute Drag and Drop Email, telephone & URL input types Form attribute Form validation HTML Imports HTML Media Capture HTML templates HTML5 form features Minimum length attribute for input fields Multiple file selection New semantic elements Number input type Offline web applications PNG favicons Pattern attribute for input fields Picture element Ping attribute Range input type Reversed attribute of ordered lists Ruby annotation Scoped CSS Search input type Session history management Spellcheck attribute Srcset and sizes attributes Text API for Canvas Toolbar/context menu Video Tracks Video element Web App Manifest accept attribute for file input async attribute for external scripts classList (DOMTokenList) contenteditable attribute (basic support) dataset & data-* attributes defer attribute for external scripts disabled attribute of the fieldset element getElementsByClassName hidden attribute indeterminate checkbox input event input placeholder attribute inputmode attribute meter element naturalWidth & naturalHeight image properties progress element readonly attribute of input and textarea elements relList (DOMTokenList) seamless attribute for iframes srcdoc attribute for iframes tabindex global attribute wbr (word break opportunity) element

JS

JS API

Ambient Light API Base64 encoding and decoding Basic console logging functions Battery Status API Beacon API Blob URLs Blob constructing BroadcastChannel CSS Font Loading CSS.supports() API Channel messaging Clipboard API Cross-document messaging CustomEvent DOM Parsing and Serialization DeviceOrientation & DeviceMotion events Document Object Model Range Document.execCommand() Efficient Script Yielding: setImmediate() Element.getBoundingClientRect() Element.insertAdjacentHTML() Element.scrollIntoViewIfNeeded() Fetch File API FileReader API FileReaderSync Filesystem & FileWriter API Full Screen API Gamepad API Geolocation Hashchange event High Resolution Time API IndexedDB Input Method Editor API Internationalization API IntersectionObserver Media Source Extensions MediaRecorder API Mutation Observer Navigation Timing API Network Information API Object RTC (ORTC) API for WebRTC Online/offline status Page Visibility PageTransitionEvent Payment Request API Pointer events PointerLock API Printing Events Promises Proximity API Push API Resource Timing Screen Orientation Selection API Server-sent events Service Workers Shared Web Workers Speech Recognition API Speech Synthesis API TextEncoder & TextDecoder Touch events URL API URLSearchParams User Timing API Vibration API Web Animations API Web Audio API Web Bluetooth Web MIDI API Web Notifications Web SQL Database Web Sockets Web Storage - name/value pairs Web Workers WebRTC Peer-to-peer connections WebVR API XMLHttpRequest advanced features document.currentScript document.evaluate & XPath getComputedStyle getUserMedia/Stream API matchMedia matches() DOM method maxlength attribute for input and textarea elements navigator.hardwareConcurrency requestAnimationFrame requestIdleCallback scrollIntoView

PNG

Other

DOM

Security

SVG