HTML5 creative

An HTML5 creative is a display ad built with HTML, CSS and JavaScript, usually delivered as a ZIP of code and assets, that can animate, adapt to the screen and respond to taps and clicks.

HTML5 replaced Flash as the format for rich display ads. The creative runs like a small web page inside the ad slot, often inside an iframe that keeps it apart from the publisher's page. Each ad platform sets its own rules. Google Ads, for example, accepts a ZIP containing HTML and, optionally, CSS, JS, GIF, PNG, JPG, JPEG and SVG files. The file must be 600 KB or smaller, images must sit inside the ZIP, and an account must apply for HTML5 access (Google Ads Help, accessed 9 November 2026).

Clicks need special handling. The ad server must supply the click-through URL so it can count clicks, which is why platforms ask for an exit or click tag instead of a hard-coded link. In apps, HTML5 creatives run in the SDK's web view and use MRAID to talk to the app. Weight matters everywhere: heavy files slow the page, drain batteries and can hurt viewability.

Example: A 300x250 HTML5 banner contains index.html, one script, one stylesheet and three images. Zipped, it weighs 180 KB, well inside Google's 600 KB limit. It uses the platform's click tag, so the ad server records each click before the landing page opens.

Related terms: DCO, MRAID, creative wrapper, ad server, viewability.

Authoritative source: Google Ads Help, "Uploaded display ads specifications", section "HTML5 ads" (accessed 9 November 2026).

Read the full guide: DCO engineering: HTML5 creative pipelines.