Fallbacks for HTTP 404 images in HTML and JavaScript

Your images are 404ing all over the place. You’ve got an angry email from a client. Their site is “broken”, images aren’t loading, cumulative layout shift is running riot, and everything is messed up. The crowds are mocking your broken code on Twitter. A fun GIF loaded via a Giphy URL no longer exists. And someone has accidentally deleted an image from the CMS.

Now, whilst you can’t control third-party URLs or user errors in a CMS, you can prevent …

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