diff --git a/web/pdf_find_controller.js b/web/pdf_find_controller.js
index f5f24140787b21..239706930f04f1 100644
--- a/web/pdf_find_controller.js
+++ b/web/pdf_find_controller.js
@@ -517,6 +517,14 @@ class PDFFindController {
     });
   }
 
+  /**
+   * Updates scroll so that the match appears into view.
+   *
+   * @param {HTMLElement} element
+   * @param {number} selectedLeft
+   * @param {number} pageIndex
+   * @param {number} matchIndex
+   */
   scrollMatchIntoView({
     element = null,
     selectedLeft = 0,
diff --git a/web/pdf_page_view.js b/web/pdf_page_view.js
index 12c80b4ef6dcbb..4ab07f759d758f 100644
--- a/web/pdf_page_view.js
+++ b/web/pdf_page_view.js
@@ -513,6 +513,22 @@ class PDFPageView {
     }
   }
 
+  /**
+   * @typedef {Object} PDFPageViewUpdateParameters
+   *
+   * @property {number} [scale] The new scale, if specified.
+   * @property {number} [rotation] The new rotation, if specified.
+   * @property {Promise<OptionalContentConfig>} [optionalContentConfigPromise]
+   *   A promise that is resolved with an {@link OptionalContentConfig} instance.
+   *   The default value is `null`.
+   * @property {number} [drawingDelay]
+   */
+
+  /**
+   * Update page view by eitheir modifiying scale or rotation.
+   *
+   * @param {PDFPageViewUpdateParameters}
+   */
   update({
     scale = 0,
     rotation = null,
diff --git a/web/ui_utils.js b/web/ui_utils.js
index a5d397b50bbdbd..b557ee82a37c17 100644
--- a/web/ui_utils.js
+++ b/web/ui_utils.js
@@ -104,9 +104,11 @@ class OutputScale {
 
 /**
  * Scrolls specified element into view of its parent.
- * @param {Object} element - The element to be visible.
- * @param {Object} spot - An object with optional top and left properties,
+ * @param {HTMLElement} element - The element to be visible.
+ * @param {Object} [spot] - An object with optional top and left properties,
  *   specifying the offset from the top left edge.
+ * @param {number} [spot.left]
+ * @param {number} [spot.top]
  * @param {boolean} [scrollMatches] - When scrolling search results into view,
  *   ignore elements that either: Contains marked content identifiers,
  *   or have the CSS-rule `overflow: hidden;` set. The default value is `false`.