ript) Get a live preview View the landing page screenshot, URL, and query parameters View network timelines, load times, file sizes, and more to ensure ads are compliant Share with clients and get feedback What is an HTML ad tag? An HTML ad tag is a snippet of HTML markup that will load an ad in a web browser. The HTML often includes JavaScript, and it tells the browser how, where and when to load the ad. Here's an example of an HTML ad tag from Google Campaign Manager 360. You can also test HTML5 ads and VAST video tags using our other tools: