diff --git a/phpBB/assets/javascript/phpbb-avatars.js b/phpBB/assets/javascript/phpbb-avatars.js
index 3d793dda9c..41f14112f0 100644
--- a/phpBB/assets/javascript/phpbb-avatars.js
+++ b/phpBB/assets/javascript/phpbb-avatars.js
@@ -11,11 +11,22 @@ phpbb.avatars = {
 	cropper: null,
 	image: null,
 
-	buttons: $('#avatar-cropper-buttons'),
-	box: $('#avatar-box'),
-	data: $('#avatar-cropper-data'),
-	input: $('#avatar_upload_file'),
-	driver: $('#avatar_driver'),
+	/** @type {jQuery} */
+	$buttons: $('#avatar-cropper-buttons'),
+
+	/** @type {jQuery} */
+	$box: $('#avatar-box'),
+
+	/** @type {jQuery} */
+	$data: $('#avatar-cropper-data'),
+
+	/** @type {jQuery} */
+	$input: $('#avatar_upload_file'),
+
+	/** @type {jQuery} */
+	$driver: $('#avatar_driver'),
+
+	/** @type {string} */
 	driverUpload: 'avatar_driver_upload',
 
 	/**
@@ -28,9 +39,9 @@ phpbb.avatars = {
 		}
 
 		// Correctly position the cropper buttons
-		this.buttons.appendTo(this.box);
+		this.$buttons.appendTo(this.$box);
 
-		this.image = this.box.children('img');
+		this.image = this.$box.children('img');
 
 		this.bindInput();
 		this.bindSelect();
@@ -40,11 +51,11 @@ phpbb.avatars = {
 	 * Destroy (undo) any initialisation.
 	 */
 	destroy: function() {
-		this.buttons.find('[data-cropper-action]').off('click.phpbb.avatars')
+		this.$buttons.find('[data-cropper-action]').off('click.phpbb.avatars');
 		this.image.off('crop.phpbb.avatars');
 
-		this.data.val('');
-		this.buttons.hide();
+		this.$data.val('');
+		this.$buttons.hide();
 
 		if (this.cropper !== null) {
 			this.cropper.destroy();
@@ -58,10 +69,10 @@ phpbb.avatars = {
 	 * Otherwise if the "upload" driver is (re-)selected, and it has a value, initialise it.
 	 */
 	bindSelect: function() {
-		this.driver.on('change', function() {
+		this.$driver.on('change', function() {
 			if ($(this).val() === phpbb.avatars.driverUpload) {
-				if (phpbb.avatars.input.val() !== '') {
-					phpbb.avatars.input.trigger('change');
+				if (phpbb.avatars.$input.val() !== '') {
+					phpbb.avatars.$input.trigger('change');
 				}
 			} else {
 				phpbb.avatars.destroy();
@@ -76,8 +87,8 @@ phpbb.avatars = {
 	 * Otherwise the cropper is destroyed.
 	 */
 	bindInput: function() {
-		this.input.on('change', function() {
-			var fileReader = new FileReader;
+		this.$input.on('change', function() {
+			const fileReader = new FileReader();
 
 			if (this.files[0].type.match('image.*')) {
 				fileReader.readAsDataURL(this.files[0]);
@@ -86,7 +97,7 @@ phpbb.avatars = {
 					phpbb.avatars.image.cropper('destroy').attr('src', this.result).addClass('avatar');
 					phpbb.avatars.initCropper();
 					phpbb.avatars.initButtons();
-				}
+				};
 			} else {
 				phpbb.avatars.destroy();
 			}
@@ -102,10 +113,9 @@ phpbb.avatars = {
 	 * For example: data-cropper-action="move,0,10" which results in $().cropper('move', 0, 10)
 	 */
 	initButtons: function() {
-
-		this.buttons.show().find('[data-cropper-action]').off('click.phpbb.avatars').on('click.phpbb.avatars', function() {
-			var option = $(this).data('cropper-action').split(',');
-			var action = option[0];
+		this.$buttons.show().find('[data-cropper-action]').off('click.phpbb.avatars').on('click.phpbb.avatars', function() {
+			const option = $(this).data('cropper-action').split(',');
+			const action = option[0];
 
 			if (typeof phpbb.avatars.cropper[action] === 'function') {
 				// Special case: flip, set it to the opposite value (-1 and 1).
@@ -150,9 +160,9 @@ phpbb.avatars = {
 	 * @param {object} event
 	 */
 	onCrop: function(event) {
-		var data = phpbb.avatars.data.data();
-		var width = event.detail.width;
-		var height = event.detail.height;
+		const data = phpbb.avatars.$data.data();
+		const width = event.detail.width;
+		const height = event.detail.height;
 
 		if (width < data.minWidth || width > data.maxWidth ||
 			height < data.minHeight || height > data.maxHeight
@@ -163,7 +173,7 @@ phpbb.avatars = {
 			});
 		}
 
-		phpbb.avatars.data.val(JSON.stringify(phpbb.avatars.cropper.getData(true)));
+		phpbb.avatars.$data.val(JSON.stringify(phpbb.avatars.cropper.getData(true)));
 	},
 };