diff --git a/CONFIGURATION.md b/CONFIGURATION.md
index 0470cab..dee59a4 100644
--- a/CONFIGURATION.md
+++ b/CONFIGURATION.md
@@ -234,6 +234,7 @@ listen: :1965
 # Custom content types
 types:
   .json: application/json; charset=UTF-8
+  .js: application/javascript; charset=UTF-8
 
 # Hosts and paths to serve
 hosts:
diff --git a/serve_https.go b/serve_https.go
index e75e6aa..0f28ba2 100644
--- a/serve_https.go
+++ b/serve_https.go
@@ -183,11 +183,15 @@ func serveHTTPS(w http.ResponseWriter, r *http.Request) (int, int64, string) {
 				fileExt := strings.ToLower(filepath.Ext(filePath))
 				if fileExt == ".gmi" || fileExt == ".gemini" {
 					result = gmitohtml.Convert([]byte(data), r.URL.String())
-				} else if fileExt == ".htm" || fileExt == ".html" {
-					result = data
 				} else {
 					result = data
-					contentType = plainType
+					if fileExt == ".htm" || fileExt == ".html" {
+						// HTML content type already set
+					} else if customType := config.Types[filepath.Ext(filePath)]; customType != "" {
+						contentType = customType
+					} else {
+						contentType = plainType
+					}
 				}
 
 				status := http.StatusOK