identifiers can contain a dollar sign

src/ace/mode/JavaScriptHighlightRules.js

@@ -78,7 +78,9 @@ JavaScriptHighlightRules = function() {
                 else
                     return "identifier";
             },
-            regex : "[a-zA-Z_][a-zA-Z0-9_]*\\b"
+            // TODO: Unicode escape sequences
+            // TODO: Unicode identifiers
+            regex : "[a-zA-Z_$][a-zA-Z0-9_$]*\\b"
         }, {
             token : "operator",
             regex : "!|\\$|%|&|\\*|\\-\\-|\\-|\\+\\+|\\+|~|===|==|=|!=|!==|<=|>=|<<=|>>=|>>>=|<>|<|>|!|&&|\\|\\||\\?\\:|\\*=|%=|\\+=|\\-=|&=|\\^=|\\b(in|instanceof|new|delete|typeof|void)"