diff --git a/R/htmlClassManipulation.R b/R/htmlClassManipulation.R
index 04db5da..0869b94 100644
--- a/R/htmlClassManipulation.R
+++ b/R/htmlClassManipulation.R
@@ -41,7 +41,8 @@ htmlRemoveClasses <- function(el, classes) {
 #' htmlButtonStyle(x, "warning")
 htmlButtonStyle <- function(el, style) {
   stopifnot(style %in% c(
-    "default", "primary", "info", "warning", "success", "danger", "link"
+    "default", "primary", "secondary", "info", "warning", "success", "danger",
+    "link"
   ))
   el <- htmlRemoveClasses(el, "btn-default")
   el <- htmlAddClasses(el, paste0("btn-", style))