diff --git a/inst/rmarkdown/templates/revealjs_presentation/resources/default.html b/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
index 5fd2a7f..d06e13b 100644
--- a/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
+++ b/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
@@ -615,7 +615,7 @@
 $endif$
 $if(transitionSpeed)$
         // Transition speed
-        transitionSpeed: '$transitionSpeed$', // default/fast/slow
+        transitionSpeed: $transitionSpeed$, // default/fast/slow
 $endif$
 $if(backgroundTransition)$
         // Transition style for full page slide backgrounds
@@ -627,19 +627,19 @@
 $endif$
 $if(parallaxBackgroundImage)$
         // Parallax background image
-        parallaxBackgroundImage: '$parallaxBackgroundImage$', // e.g. "'https://s3.amazonaws.com/hakim-static/reveal-js/reveal-parallax-1.jpg'"
+        parallaxBackgroundImage: $parallaxBackgroundImage$, // e.g. "'https://s3.amazonaws.com/hakim-static/reveal-js/reveal-parallax-1.jpg'"
 $endif$
 $if(parallaxBackgroundSize)$
         // Parallax background size
-        parallaxBackgroundSize: '$parallaxBackgroundSize$', // CSS syntax, e.g. "2100px 900px"
+        parallaxBackgroundSize: $parallaxBackgroundSize$, // CSS syntax, e.g. "2100px 900px"
 $endif$
 $if(parallaxBackgroundHorizontal)$
         // Amount to move parallax background (horizontal and vertical) on slide change
         // Number, e.g. 100
-        parallaxBackgroundHorizontal: '$parallaxBackgroundHorizontal$',
+        parallaxBackgroundHorizontal: $parallaxBackgroundHorizontal$,
 $endif$
 $if(parallaxBackgroundVertical)$
-        parallaxBackgroundVertical: '$parallaxBackgroundVertical$',
+        parallaxBackgroundVertical: $parallaxBackgroundVertical$,
 $endif$
 $if(width)$
         // The "normal" size of the presentation, aspect ratio will be preserved