diff --git a/lib/ace/mode/javascript_highlight_rules.js b/lib/ace/mode/javascript_highlight_rules.js
index 3dd063f2..38fe7100 100644
--- a/lib/ace/mode/javascript_highlight_rules.js
+++ b/lib/ace/mode/javascript_highlight_rules.js
@@ -52,7 +52,7 @@ JavaScriptHighlightRules = function() {
     );
     
     var buildinConstants = lang.arrayToMap(
-        ("true|false|null|undefined|Infinity|NaN|undefined").split("|")
+        ("null|Infinity|NaN|undefined").split("|")
     );
     
     var futureReserved = lang.arrayToMap(
@@ -96,6 +96,9 @@ JavaScriptHighlightRules = function() {
         }, {
             token : "constant.numeric", // float
             regex : "[+-]?\\d+(?:(?:\\.\\d*)?(?:[eE][+-]?\\d+)?)?\\b"
+        }, {
+            token : "constant.boolean", // float
+            regex : "(?:true|false)\\b"
         }, {
             token : function(value) {
                 if (value == "this")