Why We Ditched iFrames for Our Testimonial Widget (And Wrote 1,000 Lines of Vanilla JS Instead)

Every embeddable widget tutorial recommends an iFrame. Drop it in, it's isolated, it can't affect the host page, done. We followed that advice for the first version of Proofly 's Wall of Love embed. It lasted about three weeks before we tore it out. The problems weren't subtle. They showed up immediately, in the first round of user testing, on every host site that wasn't a plain white page. What broke Height synchronization. An iFrame doesn't know how tall its content is unless you tell it. Our