New in Chrome 154: iframes that automatically resize themselves to their content

Chrome 154 introduces responsively-sized iframes, allowing an iframe to automatically resize to match the intrinsic size of its embedded document. This requires a two-way opt-in: the embedder sets the frame-sizing CSS property (content-height or content-width) on the iframe, and the embedded document includes a meta tag (responsive-embedded-sizing) to allow size communication to the parent, restricting it by origin via allow-origins. The embedded page calls window.requestResize() to notify the parent of new size after load. This is aimed at use cases like third-party comment widgets, social media embeds, and multi-step forms in iframes. Full details are covered in a companion article on developer.chrome.com.

Source: https://www.bram.us/2026/09/23/responsive-iframes. 8 Sync News only summarizes and links out; content copyright belongs to the authors and original sources.