const loanpassOrigin = "https://app.loanpass.io"; const iframe = document.createElement("iframe"); iframe.src = `https://app.loanpass.io/frame-redirect/dominionwholesale`; iframe.addEventListener("load", () => { // Connect to send and receive messages iframe.contentWindow.postMessage({ message: "connect" }, loanpassOrigin); }); // Attach the message listener window.addEventListener("message", event => { // Validate the message came from the LoanPASS (iframe) if (event.origin !== loanpassOrigin) { console.warn("Received message from unexpected origin", event); return; } // ... do something with the message ... console.log("Received message", event.data); }); var container = document.getElementById("loanpass-container"); container.appendChild(iframe);