Fixing GSAP CDN issues for HTML5 banner builds served via Doubleclick Studio

Where to find the Doubleclick Studio CDN scripts for GSAP and how to resolve samesite cookie warnings in the console.

Last updated on 19 August, 2020, 11:07pm by keston


Recent updates to Google Chrome (First observed 12 August 2020) appear to be causing intermittent issues if a HTML5 banner requests hosted scripts at different domain – which both implement cookies.

Should anyone care? Maybe

If for example, you have a HTML5 banner that calls two javascript libraries, say the Greensock library and maybe the Doubleclick Enabler, unless they are being called via the same CDN, you might notice warnings in your developer console.



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These warnings have been around for many months and until now, haven’t caused any breaking changes. However, last week – I was working on some ads and Chrome decided to refuse connection to the cloudflare CDN is was using at the time, citing cross-site resource issues with cookies. This DID cause a breaking change. Possibly Cloudflare started dropping cookies, where it previously did not. Maybe it's the start of things to come. 


This should have been a straightforward CDN link swap, however, Google support docs (at the time of writing) don’t include a CDN link for GSAP Tweenmax.  


I have since spoken the Doubleclick support and they say they are working to update the official CDN page


GSAP CDN links for the popular adservers

Jack @GSAP has also posted a list of links for plugins

What about other adservers like Sizmek and Flashtalking?

The same is likely true for Sizmek and Flashtalking ads, tested in Chrome although those platforms already reject CDN references outside of their own, as part of their QA process.

It’s best practice to call scripts via the same CDN for banner builds in general, however, if you inherent a build from elsewhere and come across the issues described (or your client changes the adserver specs last minute) – don’t panic, give the CDN references some early attention.


Hope this helps somebody, somewhere, at some time.