diff --git a/Documentation/CMakeLists.txt b/Documentation/CMakeLists.txt
index 01547f79d85..a487d69966d 100644
--- a/Documentation/CMakeLists.txt
+++ b/Documentation/CMakeLists.txt
@@ -1,6 +1,6 @@
 project(Documentation NONE)
 
-# Visuall Studio users might appreciate this
+# Visual Studio users might appreciate this
 # set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 
 macro(subdirlist result curdir)
@@ -81,8 +81,8 @@ find_package(PythonInterp 2.6.8)
 
 if(DOXYGEN_FOUND)
   # set up the directories and variables
-  option(CGAL_DOC_MATHJAX_LOCATION "The location of MathJax to be used for the documentation." 
-    "http://cdn.mathjax.org/mathjax/latest")
+  set(CGAL_DOC_MATHJAX_LOCATION "http://cdn.mathjax.org/mathjax/latest"
+      CACHE STRING "The location of MathJax to be used for the documentation.")
 
   set(CGAL_DOC_OUTPUT_DIR "${CMAKE_BINARY_DIR}/doc_output")
   file(MAKE_DIRECTORY "${CGAL_DOC_OUTPUT_DIR}")