+/*!
+@function
+@abstract Creates a JavaScript context group.
+@discussion A JSContextGroup associates JavaScript contexts with one another.
+ Contexts in the same group may share and exchange JavaScript objects. Sharing and/or exchanging
+ JavaScript objects between contexts in different groups will produce undefined behavior.
+ When objects from the same context group are used in multiple threads, explicit
+ synchronization is required.
+@result The created JSContextGroup.
+*/
+JS_EXPORT JSContextGroupRef JSContextGroupCreate() AVAILABLE_IN_WEBKIT_VERSION_4_0;
+
+/*!
+@function
+@abstract Retains a JavaScript context group.
+@param group The JSContextGroup to retain.
+@result A JSContextGroup that is the same as group.
+*/
+JS_EXPORT JSContextGroupRef JSContextGroupRetain(JSContextGroupRef group) AVAILABLE_IN_WEBKIT_VERSION_4_0;
+
+/*!
+@function
+@abstract Releases a JavaScript context group.
+@param group The JSContextGroup to release.
+*/
+JS_EXPORT void JSContextGroupRelease(JSContextGroupRef group) AVAILABLE_IN_WEBKIT_VERSION_4_0;
+