CSP Mistakes with JSFiddle Embeds and How to Fix Them
JSFiddle embeds look harmless until your CSP blocks them and your page turns into an empty rectangle. I’ve seen this happen a lot: someone adds a fiddle iframe to docs, tutorials, or a demo page, then ships a tight CSP and suddenly the embed refuses to load. The browser console says something vague about frame-src, maybe script-src, and now everyone is guessing. JSFiddle embeds are a good example of how CSP failures usually come from one or two small misunderstandings, not from some giant policy disaster. Here are the mistakes I see most often, and the fixes that actually work. ...