<script> const child = window.open(`./window-open-postMessage.html`, '', 'show=no,nodeIntegration=yes,contextIsolation=no') window.onmessage = (e) => { if (e.data === 'ready') { child.postMessage('testing', '*') } else { require('electron').ipcRenderer.send('complete', {eventOrigin: e.origin, ...JSON.parse(e.data)}) } } </script>