Send data from parent window to child popup window - PostMessage API

March 16, 2022

A child enjoying a soft drink on a swing over a river Photo by Jordan Rowland on Unsplash

Post Message API - Sending data from parent window to popup window:

You can use the Post Message API to communicate between parent and child popup windows as well. The only catch is, you'll need the child window reference in the parent.


/* Step 1 : Open popup */
const popup ="", "_blank");

/* Step 2 : Add message event listener in popup window
Open the console of the newly opened window and add this code */
window.addEventListener("message", function(event) {
  if (typeof( === "string") {
    alert("Hello from the other side! " +;

/* Step 3 : Send a message to popup */
const message = "Hello there!"
popup.postMessage(message, "*");

Parent window to popup communication - Demo

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