--- a/testing/marionette/element.js
+++ b/testing/marionette/element.js
@@ -1066,17 +1066,17 @@ const boolEls = {
   track: ["default"],
   video: ["autoplay", "controls", "loop", "muted"],
 };
 
 /**
  * Tests if the attribute is a boolean attribute on element.
  *
  * @param {DOMElement} el
- *     Element to test if |attr| is a boolean attribute on.
+ *     Element to test if <var>attr</var> is a boolean attribute on.
  * @param {string} attr
  *     Attribute to test is a boolean attribute.
  *
  * @return {boolean}
  *     True if the attribute is boolean, false otherwise.
  */
 element.isBooleanAttribute = function(el, attr) {
   if (el.namespaceURI !== XMLNS) {