diff --git a/src/display/display_utils.js b/src/display/display_utils.js
index b1292858b4110..aa744a4878afb 100644
--- a/src/display/display_utils.js
+++ b/src/display/display_utils.js
@@ -447,7 +447,10 @@ function addLinkAttributes(link, { url, target, rel, enabled = true } = {}) {
   link.rel = typeof rel === "string" ? rel : DEFAULT_LINK_REL;
 }
 
-// Gets the file name from a given URL.
+/**
+ * Gets the file name from a given URL.
+ * @param {string} url
+ */
 function getFilenameFromUrl(url) {
   const anchor = url.indexOf("#");
   const query = url.indexOf("?");
@@ -521,6 +524,10 @@ function isValidFetchUrl(url, baseUrl) {
   }
 }
 
+/**
+ * @param {string} src
+ * @returns {Promise<void>}
+ */
 function loadScript(src) {
   return new Promise((resolve, reject) => {
     const script = document.createElement("script");
diff --git a/src/shared/util.js b/src/shared/util.js
index 27ea302839180..525f40461a2ef 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -467,6 +467,9 @@ class AbortException extends BaseException {}
 
 const NullCharactersRegExp = /\x00/g;
 
+/**
+ * @param {string} str
+ */
 function removeNullCharacters(str) {
   if (typeof str !== "string") {
     warn("The argument for removeNullCharacters must be a string.");