--- a/testing/marionette/element.js
+++ b/testing/marionette/element.js
@@ -598,17 +598,25 @@ function findElements(using, value, root
       }
       return [];
 
     default:
       throw new InvalidSelectorError(`No such strategy: ${using}`);
   }
 }
 
-/** Determines if |obj| is an HTML or JS collection. */
+/**
+ * Determines if <var>obj<var> is an HTML or JS collection.
+ *
+ * @param {*} seq
+ *     Type to determine.
+ *
+ * @return {boolean}
+ *     True if <var>seq</va> is collection.
+ */
 element.isCollection = function(seq) {
   switch (Object.prototype.toString.call(seq)) {
     case "[object Arguments]":
     case "[object Array]":
     case "[object FileList]":
     case "[object HTMLAllCollection]":
     case "[object HTMLCollection]":
     case "[object HTMLFormControlsCollection]":