diff --git a/config.go b/config.go
index cadb4b5..51193e5 100644
--- a/config.go
+++ b/config.go
@@ -179,6 +179,10 @@ type Config struct {
 	// Applies custom CSS styles.
 	// default: ""
 	CustomStyle template.CSS `json:"-"`
+
+	// Applies custom JavaScript scripts.
+	// default ""
+	CustomScript template.JS `json:"-"`
 }
 
 type FilterConfig struct {
diff --git a/index.go b/index.go
index aac7c87..d90607f 100644
--- a/index.go
+++ b/index.go
@@ -17,6 +17,11 @@ const indexTmpl string = `
         {{.CustomStyle}}
       </style>
     {{- end}}
+    {{- if .CustomScript}}
+      <script>
+        {{.CustomScript}}
+      </script>
+    {{- end}}
   </head>
   <body>
     <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" style="position:absolute;width:0;height:0">
