diff --git a/public/js/common.js b/public/js/common.js
new file mode 100644
index 0000000..0406dbf
--- /dev/null
+++ b/public/js/common.js
@@ -0,0 +1,23 @@
+/**
+ * Set an alpine.js property
+ *
+ * @function setProp
+ * @param {string} key - Key of the data property
+ * @param {*} prop - The data property
+ * @param {string} selector - The jQuery selector to the root element
+ */
+const setProp = (key, prop, selector = '#root') => {
+	$(selector).get(0).__x.$data[key] = prop;
+};
+
+/**
+ * Get an alpine.js property
+ *
+ * @function getProp
+ * @param {string} key - Key of the data property
+ * @param {string} selector - The jQuery selector to the root element
+ * @return {*} The data property
+ */
+const getProp = (key, selector = '#root') => {
+	return $(selector).get(0).__x.$data[key];
+};
diff --git a/public/js/download-manager.js b/public/js/download-manager.js
index 0dec026..6136232 100644
--- a/public/js/download-manager.js
+++ b/public/js/download-manager.js
@@ -1,25 +1,3 @@
-/**
- * Set an alpine.js property
- *
- * @function setProp
- * @param {string} key - Key of the data property
- * @param {*} prop - The data property
- */
-const setProp = (key, prop) => {
-	$('#root').get(0).__x.$data[key] = prop;
-};
-
-/**
- * Get an alpine.js property
- *
- * @function getProp
- * @param {string} key - Key of the data property
- * @return {*} The data property
- */
-const getProp = (key) => {
-	return $('#root').get(0).__x.$data[key];
-};
-
 /**
  * Get the current queue and update the view
  *
diff --git a/public/js/reader.js b/public/js/reader.js
index 6d44a06..f7b26c3 100644
--- a/public/js/reader.js
+++ b/public/js/reader.js
@@ -61,28 +61,6 @@ const updateMode = (mode, targetPage) => {
 	});
 };
 
-/**
- * Set an alpine.js property
- *
- * @function setProp
- * @param {string} key - Key of the data property
- * @param {*} prop - The data property
- */
-const setProp = (key, prop) => {
-	$('#root').get(0).__x.$data[key] = prop;
-};
-
-/**
- * Get an alpine.js property
- *
- * @function getProp
- * @param {string} key - Key of the data property
- * @return {*} The data property
- */
-const getProp = (key) => {
-	return $('#root').get(0).__x.$data[key];
-};
-
 /**
  * Get dimension of the pages in the entry from the API and update the view
  */
diff --git a/src/views/components/head.html.ecr b/src/views/components/head.html.ecr
index d2421d0..e4fdfcf 100644
--- a/src/views/components/head.html.ecr
+++ b/src/views/components/head.html.ecr
@@ -14,5 +14,6 @@
   <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
   <script type="module" src="https://cdn.jsdelivr.net/gh/alpinejs/alpine@v2.5.0/dist/alpine.min.js"></script>
   <script nomodule src="https://cdn.jsdelivr.net/gh/alpinejs/alpine@v2.5.0/dist/alpine-ie11.min.js" defer></script>
+  <script src="<%= base_url %>js/common.js"></script>
   <script src="<%= base_url %>js/theme.js"></script>
 </head>