diff --git a/teavm-jso-impl/pom.xml b/teavm-jso-impl/pom.xml
index cfc991f5f..641ddd518 100644
--- a/teavm-jso-impl/pom.xml
+++ b/teavm-jso-impl/pom.xml
@@ -38,6 +38,11 @@ xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xs
       <artifactId>teavm-jso</artifactId>
       <version>${project.version}</version>
     </dependency>
+    <dependency>
+      <groupId>org.mozilla</groupId>
+      <artifactId>rhino</artifactId>
+      <version>1.7.7</version>
+    </dependency>
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
diff --git a/teavm-jso-impl/src/main/java/org/teavm/jso/plugin/JSBodyGenerator.java b/teavm-jso-impl/src/main/java/org/teavm/jso/plugin/JSBodyGenerator.java
index 0e496c4e7..4afc70de1 100644
--- a/teavm-jso-impl/src/main/java/org/teavm/jso/plugin/JSBodyGenerator.java
+++ b/teavm-jso-impl/src/main/java/org/teavm/jso/plugin/JSBodyGenerator.java
@@ -16,11 +16,22 @@
 package org.teavm.jso.plugin;
 
 import java.io.IOException;
+import java.io.StringReader;
 import java.util.List;
+import org.mozilla.javascript.CompilerEnvirons;
+import org.mozilla.javascript.IRFactory;
+import org.mozilla.javascript.ast.AstNode;
+import org.mozilla.javascript.ast.AstRoot;
+import org.mozilla.javascript.ast.NodeVisitor;
 import org.teavm.codegen.SourceWriter;
 import org.teavm.javascript.spi.Generator;
 import org.teavm.javascript.spi.GeneratorContext;
-import org.teavm.model.*;
+import org.teavm.model.AnnotationReader;
+import org.teavm.model.AnnotationValue;
+import org.teavm.model.CallLocation;
+import org.teavm.model.ClassReader;
+import org.teavm.model.MethodReader;
+import org.teavm.model.MethodReference;
 
 /**
  *
@@ -37,51 +48,24 @@ public class JSBodyGenerator implements Generator {
 
         int bodyParamCount = isStatic ? method.parameterCount() : method.parameterCount() - 1;
 
-        writer.append("if (!").appendMethodBody(methodRef).append(".$native)").ws().append('{').indent().newLine();
-        writer.appendMethodBody(methodRef).append(".$native").ws().append('=').ws().append("function(");
-        int count = method.parameterCount();
-        for (int i = 0; i < count; ++i) {
-            if (i > 0) {
-                writer.append(',').ws();
-            }
-            writer.append('_').append(context.getParameterName(i + 1));
+        CompilerEnvirons env = new CompilerEnvirons();
+        env.setRecoverFromErrors(true);
+        IRFactory factory = new IRFactory(env, new TeaVMErrorReporter(context.getDiagnostics(),
+                new CallLocation(methodRef)));
+        String script = annot.getValue("script").getString();
+        AstRoot rootNode;
+        try {
+            rootNode = factory.parse(new StringReader(script), null, 0);
+        } catch (IOException e) {
+            context.getDiagnostics().error(new CallLocation(methodRef), "IO error parsing JSBody script");
+            return;
         }
-        writer.append(')').ws().append('{').softNewLine().indent();
 
-        writer.append("return (function(");
-        for (int i = 0; i < bodyParamCount; ++i) {
-            if (i > 0) {
-                writer.append(',').ws();
+        rootNode.visit(new NodeVisitor() {
+            @Override
+            public boolean visit(AstNode node) {
+                return false;
             }
-            String name = paramNames.get(i).getString();
-            writer.append(name);
-        }
-        writer.append(')').ws().append('{').softNewLine().indent();
-        writer.append(annot.getValue("script").getString()).softNewLine();
-        writer.outdent().append("})");
-        if (!isStatic) {
-            writer.append(".call");
-        }
-        writer.append('(');
-        for (int i = 0; i < count; ++i) {
-            if (i > 0) {
-                writer.append(',').ws();
-            }
-            writer.append('_').append(context.getParameterName(i + 1));
-        }
-        writer.append(");").softNewLine();
-        writer.outdent().append("};").softNewLine();
-        writer.appendMethodBody(methodRef).ws().append('=').ws().appendMethodBody(methodRef).append(".$native;")
-                .softNewLine();
-        writer.outdent().append("}").softNewLine();
-
-        writer.append("return ").appendMethodBody(methodRef).append('(');
-        for (int i = 0; i < count; ++i) {
-            if (i > 0) {
-                writer.append(',').ws();
-            }
-            writer.append(context.getParameterName(i + 1));
-        }
-        writer.append(");").softNewLine();
+        });
     }
 }
diff --git a/teavm-jso-impl/src/main/java/org/teavm/jso/plugin/TeaVMErrorReporter.java b/teavm-jso-impl/src/main/java/org/teavm/jso/plugin/TeaVMErrorReporter.java
new file mode 100644
index 000000000..8a95374de
--- /dev/null
+++ b/teavm-jso-impl/src/main/java/org/teavm/jso/plugin/TeaVMErrorReporter.java
@@ -0,0 +1,53 @@
+/*
+ *  Copyright 2015 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.jso.plugin;
+
+import org.mozilla.javascript.ErrorReporter;
+import org.mozilla.javascript.EvaluatorException;
+import org.teavm.diagnostics.Diagnostics;
+import org.teavm.model.CallLocation;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+public class TeaVMErrorReporter implements ErrorReporter {
+    private Diagnostics diagnostics;
+    private CallLocation location;
+
+    public TeaVMErrorReporter(Diagnostics diagnostics, CallLocation location) {
+        this.diagnostics = diagnostics;
+        this.location = location;
+    }
+
+    @Override
+    public void warning(String message, String sourceName, int line, String lineSource, int lineOffset) {
+        diagnostics.warning(location, "Error in @JSBody script line " + line + ", char " + lineOffset
+                + ": " + message);
+    }
+
+    @Override
+    public void error(String message, String sourceName, int line, String lineSource, int lineOffset) {
+        diagnostics.error(location, "Error in @JSBody script line " + line + ", char " + lineOffset
+                + ": " + message);
+    }
+
+    @Override
+    public EvaluatorException runtimeError(String message, String sourceName, int line, String lineSource,
+            int lineOffset) {
+        return null;
+    }
+}