postMessage

The postMessage API sends string or structured data between windows, iframes and workers across origins, the backbone of safe cross origin messaging. It is supported everywhere; always validate the origin of every incoming message.

Verdict

Safe to use

Category

HTML features

Browser support

Can I Use

Works in

all modern browsers

Should you use postMessage in 2026?

postMessage is present in IE8 and up, but if you need robust support for cross-frame and cross-domain communication, use EasyXDM

Polyfills and fallbacks

EasyXDM

Browser share on Can I Use Edit on GitHub