2027 Web Platform Feature Ranking

Ranked proposals (top = most important)

1. JavaScript Temporal

   A modern and extensive date/time API to replace Date.
2. Customizable/stylable <select>

   Customize the button, selected option, picker, and options with CSS.
3. Responsive iframes

   The frame-⁠sizing CSS property sizes an <iframe> to its content, avoiding scrolling within the iframe.
4. Improve interoperability of pointer events on touch devices
5. HTML <iframe allow="cross-⁠origin-⁠isolated">

   Allows cross-origin isolated features, such as SharedArrayBuffer, within iframes.
6. Extended lifetime SharedWorkers

   Gives shared workers extra time to finish work after all pages using them have closed.
7. WebUSB API

   Exposes USB-compatible devices to web pages.
8. CSS interpolate-⁠size property and calc-⁠size() function

   Allows animating to height: auto, and using intrinsic sizes in calculations.
9. Allow CSS transitioning/animating display and content-⁠visibility

   Useful for delaying display: none until an exit animation completes.
10. CSS flex-⁠wrap: balance

    Distributes items in a multi-line flex container so each line has about the same number of items.
11. Brotli support in CompressionStream and DecompressionStream
12. JavaScript CSS module imports

    import … with { type: "css" } to load CSS resources as constructable stylesheets.
13. CSS align-⁠content for centering in buttons and inputs

    Allows overriding the vertical alignment of text in form controls.
14. Correct handling of powerless and missing color components

    Fixes none and powerless components in color-⁠mix(), relative color syntax, and gradients.