diff --git a/README.md b/README.md
index e110c8a5c..ee9bb8c34 100644
--- a/README.md
+++ b/README.md
@@ -370,6 +370,8 @@ docs: [
 ]
 ```
 
+On the JavaScript side, ExDoc emits the `"exdoc:loaded"` event. This event may be called multiple times, as you navigate across pages, so initialization that should happen only once must be conditional. We recommend external scripts to use `defer`, not `async`, as shown in the examples below.
+
 ### Rendering Math
 
 If you write TeX-style math in your Markdown, such as `$\sum_{i}^{N} x_i$`, it ends up as raw text on the generated pages. To render expressions, we recommend using [KaTeX](https://katex.org/), a JavaScript library that turns expressions into graphics. To load and trigger KaTeX on every documentation page, we can insert the following HTML:
@@ -381,13 +383,17 @@ If you write TeX-style math in your Markdown, such as `$\sum_{i}^{N} x_i$`, it e
 <link href="https://cdn.jsdelivr.net/npm/katex-copytex@1.0.2/dist/katex-copytex.min.css" rel="stylesheet" type="text/css">
 <script defer src="https://cdn.jsdelivr.net/npm/katex-copytex@1.0.2/dist/katex-copytex.min.js" crossorigin="anonymous"></script>
 
-<script defer src="https://cdn.jsdelivr.net/npm/katex@0.16.4/dist/contrib/auto-render.min.js" integrity="sha384-+VBxd3r6XgURycqtZ117nYw44OOcIax56Z4dCRWbxyPt0Koah1uHoK0o4+/RRE05" crossorigin="anonymous"
-  onload="renderMathInElement(document.body, {
-    delimiters: [
-      {left: '$$', right: '$$', display: true},
-      {left: '$', right: '$', display: false},
-    ]
-  });"></script>
+<script defer src="https://cdn.jsdelivr.net/npm/katex@0.16.4/dist/contrib/auto-render.min.js" integrity="sha384-+VBxd3r6XgURycqtZ117nYw44OOcIax56Z4dCRWbxyPt0Koah1uHoK0o4+/RRE05" crossorigin="anonymous"></script>
+
+<script>
+  window.addEventListener("exdoc:loaded", () => {
+    renderMathInElement(document.body, {
+      delimiters: [
+        {left: '$$', right: '$$', display: true},
+        {left: '$', right: '$', display: false},
+      ]
+    })
+  })
 </script>
 ```
 
@@ -402,7 +408,7 @@ Snippets are also objects you may want to render in a special manner. For exampl
 <script defer src="https://cdn.jsdelivr.net/npm/vega-lite@5.1.1"></script>
 <script defer src="https://cdn.jsdelivr.net/npm/vega-embed@6.18.2"></script>
 <script>
-  document.addEventListener("DOMContentLoaded", function () {
+  window.addEventListener("exdoc:loaded", () => {
     for (const codeEl of document.querySelectorAll("pre code.vega-lite")) {
       try {
         const preEl = codeEl.parentElement;
@@ -426,12 +432,19 @@ For more details and configuration options, see [vega/vega-embed](https://github
 Similarly to the example above, if your Markdown includes Mermaid graph specification in `mermaid` code snippets:
 
 ```html
+<script defer src="https://cdn.jsdelivr.net/npm/mermaid@10.2.3/dist/mermaid.min.js"></script>
 <script>
-  function mermaidLoaded() {
-    mermaid.initialize({
-      startOnLoad: false,
-      theme: document.body.className.includes("dark") ? "dark" : "default"
-    });
+  let initialized = false;
+
+  window.addEventListener("exdoc:loaded", () => {
+    if (!initialized) {
+      mermaid.initialize({
+        startOnLoad: false,
+        theme: document.body.className.includes("dark") ? "dark" : "default"
+      });
+      initialized = true;
+    }
+
     let id = 0;
     for (const codeEl of document.querySelectorAll("pre code.mermaid")) {
       const preEl = codeEl.parentElement;
@@ -445,9 +458,8 @@ Similarly to the example above, if your Markdown includes Mermaid graph specific
         preEl.remove();
       });
     }
-  }
+  });
 </script>
-<script async src="https://cdn.jsdelivr.net/npm/mermaid@10.2.3/dist/mermaid.min.js" onload="mermaidLoaded();"></script>
 ```
 
 For more details and configuration options, see the [Mermaid usage docs](https://mermaid-js.github.io/mermaid/#/usage).
diff --git a/assets/js/content.js b/assets/js/content.js
index 8a2d5c698..e04f09eb0 100644
--- a/assets/js/content.js
+++ b/assets/js/content.js
@@ -6,8 +6,7 @@ import { settingsStore } from './settings-store'
  * corresponding to the current documentation page.
  */
 
-window.addEventListener('swup:page:view', initialize)
-initialize()
+window.addEventListener('exdoc:loaded', initialize)
 
 function initialize () {
   const notebookPath = window.location.pathname.replace(/(\.html)?$/, '.livemd')
diff --git a/assets/js/copy-button.js b/assets/js/copy-button.js
index 2272d3546..a3171e9dd 100644
--- a/assets/js/copy-button.js
+++ b/assets/js/copy-button.js
@@ -8,8 +8,7 @@ let buttonTemplate
  * Initializes copy buttons.
  */
 
-window.addEventListener('swup:page:view', initialize)
-initialize()
+window.addEventListener('exdoc:loaded', initialize)
 
 function initialize () {
   if (!('clipboard' in navigator)) return
diff --git a/assets/js/makeup.js b/assets/js/makeup.js
index cb867aa44..758255af2 100644
--- a/assets/js/makeup.js
+++ b/assets/js/makeup.js
@@ -6,8 +6,7 @@ const HIGHLIGHT_CLASS = 'hll'
  * Sets up dynamic behaviour for code blocks processed with *makeup*.
  */
 
-window.addEventListener('swup:page:view', initialize)
-initialize()
+window.addEventListener('exdoc:loaded', initialize)
 
 export function initialize () {
   // Hovering over a delimiter (bracket, parenthesis, do/end)
diff --git a/assets/js/quick-switch.js b/assets/js/quick-switch.js
index c36ef034a..08ab4b340 100644
--- a/assets/js/quick-switch.js
+++ b/assets/js/quick-switch.js
@@ -74,8 +74,7 @@ const state = {
  */
 
 if (!isEmbedded) {
-  window.addEventListener('swup:page:view', initialize)
-  initialize()
+  window.addEventListener('exdoc:loaded', initialize)
 }
 
 function initialize () {
diff --git a/assets/js/search-bar.js b/assets/js/search-bar.js
index 25e555c97..2e50e04e4 100644
--- a/assets/js/search-bar.js
+++ b/assets/js/search-bar.js
@@ -21,8 +21,7 @@ const SEARCH_CLOSE_BUTTON_SELECTOR = 'form.search-bar .search-close-button'
  */
 
 if (!isEmbedded) {
-  window.addEventListener('swup:page:view', initialize)
-  initialize()
+  window.addEventListener('exdoc:loaded', initialize)
 }
 
 function initialize () {
diff --git a/assets/js/search-page.js b/assets/js/search-page.js
index a60b95c72..7f647b4bd 100644
--- a/assets/js/search-page.js
+++ b/assets/js/search-page.js
@@ -20,8 +20,7 @@ lunr.Pipeline.registerFunction(docTrimmerFunction, 'docTrimmer')
  * Activates only on the `/search.html` page.
  */
 
-window.addEventListener('swup:page:view', initialize)
-initialize()
+window.addEventListener('exdoc:loaded', initialize)
 
 function initialize () {
   const pathname = window.location.pathname
diff --git a/assets/js/settings.js b/assets/js/settings.js
index e77cee4d7..4e21d82fe 100644
--- a/assets/js/settings.js
+++ b/assets/js/settings.js
@@ -26,8 +26,7 @@ const modalTabs = [
  * Sets up the settings modal.
  */
 
-window.addEventListener('swup:page:view', initialize)
-initialize()
+window.addEventListener('exdoc:loaded', initialize)
 
 function initialize () {
   qsAll(SETTINGS_LINK_SELECTOR).forEach(element => {
diff --git a/assets/js/sidebar/sidebar-drawer.js b/assets/js/sidebar/sidebar-drawer.js
index 00bb25130..b6f0022c8 100644
--- a/assets/js/sidebar/sidebar-drawer.js
+++ b/assets/js/sidebar/sidebar-drawer.js
@@ -11,9 +11,7 @@ const SIDEBAR_TOGGLE_SELECTOR = '.sidebar-toggle'
 const smallScreenQuery = window.matchMedia(`screen and (max-width: ${SMALL_SCREEN_BREAKPOINT}px)`)
 
 if (!isEmbedded) {
-  setDefaultSidebarState()
-
-  window.addEventListener('swup:page:view', setDefaultSidebarState)
+  window.addEventListener('exdoc:loaded', setDefaultSidebarState)
 
   const sidebar = document.getElementById('sidebar')
   const sidebarToggle = qs(SIDEBAR_TOGGLE_SELECTOR)
@@ -49,6 +47,7 @@ if (!isEmbedded) {
     sessionStorage.setItem(SIDEBAR_WIDTH_KEY, width)
     document.body.style.setProperty('--sidebarWidth', `${width}px`)
   })
+
   // We observe on mousedown because we only care about user resize.
   sidebar.addEventListener('mousedown', () => resizeObserver.observe(sidebar))
   sidebar.addEventListener('mouseup', () => resizeObserver.unobserve(sidebar))
diff --git a/assets/js/sidebar/sidebar-list.js b/assets/js/sidebar/sidebar-list.js
index 5838d61f3..a76b0dfdf 100644
--- a/assets/js/sidebar/sidebar-list.js
+++ b/assets/js/sidebar/sidebar-list.js
@@ -89,9 +89,12 @@ export function initialize () {
   })
 
   window.addEventListener('hashchange', markCurrentHashInSidebar)
-  window.addEventListener('swup:page:view', markCurrentHashInSidebar)
 
+  // We listen to swup:page:view event because we need to trigger
+  // markCurrentHashInSidebar() before scollNodeListToCurrentCategory.
+  window.addEventListener('swup:page:view', markCurrentHashInSidebar)
   markCurrentHashInSidebar()
+
   // Triggers layout, defer.
   requestAnimationFrame(scrollNodeListToCurrentCategory)
 }
diff --git a/assets/js/swup.js b/assets/js/swup.js
index b56789733..6f9fccd6b 100644
--- a/assets/js/swup.js
+++ b/assets/js/swup.js
@@ -3,6 +3,10 @@ import SwupA11yPlugin from '@swup/a11y-plugin'
 import SwupProgressPlugin from '@swup/progress-plugin'
 import { isEmbedded } from './globals'
 
+window.addEventListener('DOMContentLoaded', () => {
+  window.dispatchEvent(new Event('exdoc:loaded'))
+})
+
 if (!isEmbedded && window.location.protocol !== 'file:') {
   new Swup({
     animationSelector: false,
@@ -15,4 +19,8 @@ if (!isEmbedded && window.location.protocol !== 'file:') {
     linkSelector: 'a[href]:not([href^="/"]):not([href^="http"])',
     plugins: [new SwupA11yPlugin(), new SwupProgressPlugin({delay: 500})]
   })
+
+  window.addEventListener('swup:page:view', () => {
+    window.dispatchEvent(new Event('exdoc:loaded'))
+  })
 }
diff --git a/assets/js/tabsets.js b/assets/js/tabsets.js
index 18d722f0a..6d60eb142 100644
--- a/assets/js/tabsets.js
+++ b/assets/js/tabsets.js
@@ -6,8 +6,7 @@ const TABSET_CLOSE_COMMENT = 'tabs-close'
 const TABPANEL_HEADING_NODENAME = 'H3'
 const TABSET_CONTAINER_CLASS = 'tabset'
 
-window.addEventListener('swup:page:view', initialize)
-initialize()
+window.addEventListener('exdoc:loaded', initialize)
 
 function initialize () {
   /** @type {[Node, [NodeList, HTMLElement[]][]][]} */
diff --git a/assets/js/tooltips/tooltips.js b/assets/js/tooltips/tooltips.js
index b37b756a7..8bb5ef1b5 100644
--- a/assets/js/tooltips/tooltips.js
+++ b/assets/js/tooltips/tooltips.js
@@ -40,8 +40,7 @@ const state = {
  * Initializes tooltips handling.
  */
 
-window.addEventListener('swup:page:view', initialize)
-initialize()
+window.addEventListener('exdoc:loaded', initialize)
 
 function initialize () {
   qsAll(TOOLTIP_ACTIVATORS_SELECTOR).forEach(element => {