diff --git a/extra/javascriptcore/ffi/ffi.factor b/extra/javascriptcore/ffi/ffi.factor
index 844e169eed..6489699d4d 100644
--- a/extra/javascriptcore/ffi/ffi.factor
+++ b/extra/javascriptcore/ffi/ffi.factor
@@ -1,7 +1,8 @@
 ! Copyright (C) 2010 Doug Coleman.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: alien alien.c-types alien.libraries alien.syntax
-classes.struct combinators io.encodings.utf8 system ;
+classes.struct combinators io.encodings.utf16n
+io.encodings.utf8 system ;
 IN: javascriptcore.ffi
 
 <<
@@ -9,6 +10,7 @@ IN: javascriptcore.ffi
         { [ os macosx? ] [ "/System/Library/Frameworks/JavaScriptCore.framework/Versions/Current/JavaScriptCore" ] }
         ! { [ os winnt? ]  [ "javascriptcore.dll" ] }
         ! { [ os unix? ]  [ "libsqlite3.so" ] }
+        [ ]
     } cond cdecl add-library
 >>
 
@@ -36,7 +38,6 @@ TYPEDEF: void* JSObjectHasInstanceCallback
 TYPEDEF: void* JSObjectConvertToTypeCallback
 TYPEDEF: uint unsigned
 TYPEDEF: ushort JSChar
-! char[utf16n] for strings
 
 C-ENUM: JSPropertyAttributes
     { kJSPropertyAttributeNone       0 }
@@ -202,7 +203,7 @@ FUNCTION: void JSPropertyNameAccumulatorAddName ( JSPropertyNameAccumulatorRef a
 
 FUNCTION: JSStringRef JSStringCreateWithCharacters ( JSChar* chars, size_t numChars ) ;
 
-FUNCTION: JSStringRef JSStringCreateWithUTF8CString ( c-string[utf8] string ) ;
+FUNCTION: JSStringRef JSStringCreateWithUTF8CString ( c-string string ) ;
 
 FUNCTION: JSStringRef JSStringRetain ( JSStringRef string ) ;
 
diff --git a/extra/javascriptcore/javascriptcore-tests.factor b/extra/javascriptcore/javascriptcore-tests.factor
new file mode 100644
index 0000000000..f04ada89f2
--- /dev/null
+++ b/extra/javascriptcore/javascriptcore-tests.factor
@@ -0,0 +1,10 @@
+! Copyright (C) 2010 Doug Coleman.
+! See http://factorcode.org/license.txt for BSD license.
+USING: accessors javascriptcore kernel tools.test ;
+IN: javascriptcore.tests
+
+[ "2" ] [ "1+1" eval-js ] unit-test
+
+[ "1+shoes" eval-js ]
+[ error>> "ReferenceError: Can't find variable: shoes" = ] must-fail-with
+
diff --git a/extra/javascriptcore/javascriptcore.factor b/extra/javascriptcore/javascriptcore.factor
index 773a559d2d..eabb97df61 100644
--- a/extra/javascriptcore/javascriptcore.factor
+++ b/extra/javascriptcore/javascriptcore.factor
@@ -1,8 +1,48 @@
 ! Copyright (C) 2010 Doug Coleman.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: javascriptcore.ffi.hack kernel ;
+USING: alien.c-types alien.data byte-arrays continuations fry
+io.encodings.string io.encodings.utf8 io.files
+javascriptcore.ffi javascriptcore.ffi.hack kernel namespaces
+sequences ;
 IN: javascriptcore
 
+ERROR: javascriptcore-error error ;
+
 : with-javascriptcore ( quot -- )
     set-callstack-bounds
     call ; inline
+
+SYMBOL: js-context
+
+: with-global-context ( quot -- )
+    [
+        [ f JSGlobalContextCreate ] dip
+        [ '[ _ @ ] ]
+        [ drop '[ _ JSGlobalContextRelease ] ] 2bi
+        [ ] cleanup
+    ] with-scope ; inline
+
+: JSString>string ( JSString -- string )
+    dup JSStringGetMaximumUTF8CStringSize [ <byte-array> ] keep
+    [ JSStringGetUTF8CString drop ] [ drop ] 2bi
+    utf8 decode [ 0 = ] trim-tail ;
+
+: JSValueRef>string ( ctx JSValueRef/f -- string/f )
+    [
+        f JSValueToStringCopy
+        [ JSString>string ] [ JSStringRelease ] bi
+    ] [
+        drop f
+    ] if* ;
+
+: eval-js ( string -- result-string )
+    '[
+        [
+            dup _ JSStringCreateWithUTF8CString f f 0 JSValueRef <c-object>
+            [ JSEvaluateScript ] keep *void*
+            dup [ nip JSValueRef>string javascriptcore-error ] [ drop JSValueRef>string ] if
+        ] with-global-context
+    ] with-javascriptcore ;
+
+: eval-js-path ( path -- result-string ) utf8 file-contents eval-js ;
+