From 860c9bbe1d887cb487bdd55e4d9cf4235f84581d Mon Sep 17 00:00:00 2001
From: Michael Wyraz <michael@wyraz.de>
Date: Wed, 3 Nov 2021 21:14:45 +0100
Subject: [PATCH] Better event handling, fix race condition, make history work

---
 html/embed.js | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/html/embed.js b/html/embed.js
index a922a14..32c5b0e 100644
--- a/html/embed.js
+++ b/html/embed.js
@@ -1,4 +1,5 @@
 (function() {
+
     var iframe=document.getElementById("meshviewer-embedded")
     if (!iframe) {
         console.log("IFrame 'meshviewer-embedded' not found")
@@ -8,17 +9,27 @@
         console.log("Element 'meshviewer-embedded' seems not to be a valid iframe")
         return;
     }
-    if (document.location.hash) {
-        window.setTimeout(function() {
-            iframe.contentWindow.location.hash = document.location.hash;
-        }, 0);
-    }
+
+    function updateIframeHash() { // see https://gist.github.com/manufitoussi/7529fa882ff0b737f257
+        if(iframe.contentWindow.location.host !== "") {
+            // iframe already loaded.
+            iframe.contentWindow.location.hash = window.location.hash;
+          } else {
+            // iframe is just starting.
+            var newHash = window.location.hash;
+            var srcStr = iframe.getAttribute('src');
+            var words = srcStr.split('#');
+            var href = words[0];
+            var newSrc = href + newHash;
+            iframe.setAttribute('src', newSrc);
+          }
+    };
+
+    updateIframeHash();
     iframe.contentWindow.addEventListener("message", (event) => {
         if (event && event.data && event.data.hash) {
-            window.location.hash = event.data.hash;
+            window.location.replace(event.data.hash);
         }
     }, false);
-    window.onhashchange = function () {
-        iframe.contentWindow.location.hash = document.location.hash;
-    };
+    window.onhashchange = updateIframeHash;
 }) ();