TL;DR
An iframe embeds a fully separate web page inside another page; many chat widgets use it for isolation, though Eloqra reaches the same goal with Shadow DOM instead.
Key Points
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An iframe creates a nested browsing context with its own document, styles, and scripts, so host-page CSS and JS cannot bleed into the embedded content. [1]
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The sandbox attribute lets you strip privileges by default and re-grant only what is needed (allow-scripts, allow-forms), which is why iframes are common for untrusted third-party embeds. [2][3]
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Iframes interrupt the host page's layout flow and need their own scrolling and sizing, whereas Shadow DOM content grows naturally with the page. [4]
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Eloqra does NOT wrap its widget in an iframe; it renders the [[live-chat-widget]] inside a [[shadow-dom]] so styles stay isolated while the floating [[chat-launcher]] still positions cleanly over the page.
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Like an iframe boundary, the [[embed-code]] you paste (a tiny [[javascript-widget]] reading ELOQRA_CHAT_CONFIG) keeps Eloqra's runtime separate from your app's code.
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Cross-document messaging between an iframe and its host uses Window.postMessage, since same-origin rules otherwise block direct access. [1]