Potential fix for code scanning alert no. 142: Missing origin verification in postMessage handler

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

Author: jf205

docs/assets/js/asciinema-player.js

@@ -146,7 +146,8 @@
     } else {
       var h = [], g = String(Math.random());
       window.addEventListener("message", function (e) {
-        if (e.data === g) {
+        var trustedOrigins = ['https://www.example.com']; // Add your trusted origins here
+        if (trustedOrigins.includes(e.origin) && e.data === g) {
           var t = h;
           h = [], t.forEach(function (e) {
             e()