iframe

An Inline Frame (`<iframe>`) is an HTML element that embeds a separate, independent HTML document (a new browsing context) into the current one.

The `<iframe>` element is a core HTML tag, essential for integrating third-party resources directly into a webpage. Its primary function is to display external content—like a YouTube video player or a Google Maps location—via a simple `src` attribute pointing to the resource URL. Crucially, the embedded document operates in its own isolated environment: its CSS, JavaScript, and local storage are separate from the parent page, mitigating security risks and preventing style conflicts. Developers manage this isolation and security using attributes like `sandbox` and `allowfullscreen`. While powerful for embedding, overuse can impact page performance and SEO, so implement it with precision.

https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe