diff --git a/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptBodyDependency.java b/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptBodyDependency.java
index d056e635c..72d742454 100644
--- a/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptBodyDependency.java
+++ b/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptBodyDependency.java
@@ -79,6 +79,8 @@ public class JavaScriptBodyDependency implements DependencyListener {
         dependencyChecker.attachMethodGraph(JavaScriptConvGenerator.toJsMethod, DependencyStack.ROOT);
         dependencyChecker.attachMethodGraph(JavaScriptConvGenerator.intValueMethod, DependencyStack.ROOT);
         dependencyChecker.attachMethodGraph(JavaScriptConvGenerator.valueOfIntMethod, DependencyStack.ROOT);
+        dependencyChecker.attachMethodGraph(JavaScriptConvGenerator.booleanValueMethod, DependencyStack.ROOT);
+        dependencyChecker.attachMethodGraph(JavaScriptConvGenerator.valueOfBooleanMethod, DependencyStack.ROOT);
     }
 
     @Override
diff --git a/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptBodyGenerator.java b/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptBodyGenerator.java
index f89c13033..9a9cf809a 100644
--- a/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptBodyGenerator.java
+++ b/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptBodyGenerator.java
@@ -20,6 +20,7 @@ import java.util.List;
 import net.java.html.js.JavaScriptBody;
 import org.teavm.codegen.NamingStrategy;
 import org.teavm.codegen.SourceWriter;
+import org.teavm.javascript.Renderer;
 import org.teavm.javascript.ni.Generator;
 import org.teavm.javascript.ni.GeneratorContext;
 import org.teavm.model.*;
@@ -53,7 +54,7 @@ public class JavaScriptBodyGenerator implements Generator {
         writer.outdent().append("}).call(").append(context.getParameterName(0));
         for (int i = 0; i < args.size(); ++i) {
             writer.append(",").ws();
-            wrapParameter(writer, methodRef.getDescriptor().parameterType(i), context.getParameterName(i + 1));
+            wrapParameter(writer, context.getParameterName(i + 1));
         }
         writer.append(")").softNewLine();
         writer.append("return ");
@@ -61,22 +62,15 @@ public class JavaScriptBodyGenerator implements Generator {
         writer.append(";").softNewLine();
     }
 
-    private void wrapParameter(SourceWriter writer, ValueType type, String param) throws IOException {
-        if (type.isObject("java.lang.Object")) {
-            writer.appendMethodBody(JavaScriptConvGenerator.toJsMethod);
-            writer.append("(").append(param).append(")");
-        } else {
-            writer.append(param);
-        }
+    private void wrapParameter(SourceWriter writer, String param) throws IOException {
+        writer.appendMethodBody(JavaScriptConvGenerator.toJsMethod);
+        writer.append("(").append(param).append(")");
     }
 
     private void unwrapValue(SourceWriter writer, ValueType type, String param) throws IOException {
-        if (type.isObject("java.lang.Object")) {
-            writer.appendMethodBody(JavaScriptConvGenerator.fromJsMethod);
-            writer.append("(").append(param).append(")");
-        } else {
-            writer.append(param);
-        }
+        writer.appendMethodBody(JavaScriptConvGenerator.fromJsMethod);
+        writer.append("(").append(param).append(",").ws().append(Renderer.typeToClsString(writer.getNaming(), type))
+                .append(")");
     }
 
     private static class GeneratorJsCallback extends JsCallback {
diff --git a/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptConv.java b/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptConv.java
index 4139f076c..9d7b41127 100644
--- a/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptConv.java
+++ b/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptConv.java
@@ -29,5 +29,5 @@ public final class JavaScriptConv {
     public static native Object toJavaScript(Object obj);
 
     @GeneratedBy(JavaScriptConvGenerator.class)
-    public static native Object fromJavaScript(Object obj);
+    public static native Object fromJavaScript(Object obj, Object cls);
 }
diff --git a/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptConvGenerator.java b/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptConvGenerator.java
index e9ba59792..190f129bc 100644
--- a/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptConvGenerator.java
+++ b/teavm-html4j/src/main/java/org/teavm/html4j/JavaScriptConvGenerator.java
@@ -29,13 +29,17 @@ public class JavaScriptConvGenerator implements Generator {
     private static final String convCls = JavaScriptConv.class.getName();
     static final MethodReference intValueMethod = new MethodReference("java.lang.Integer",
             new MethodDescriptor("intValue", ValueType.INTEGER));
+    static final MethodReference booleanValueMethod = new MethodReference("java.lang.Boolean",
+            new MethodDescriptor("booleanValue", ValueType.BOOLEAN));
     static final MethodReference valueOfIntMethod = new MethodReference("java.lang.Integer",
             new MethodDescriptor("valueOf", ValueType.INTEGER, ValueType.object("java.lang.Integer")));
+    static final MethodReference valueOfBooleanMethod = new MethodReference("java.lang.Boolean",
+            new MethodDescriptor("valueOf", ValueType.BOOLEAN, ValueType.object("java.lang.Boolean")));
     private static final ValueType objType = ValueType.object("java.lang.Object");
     static final MethodReference toJsMethod = new MethodReference(convCls, new MethodDescriptor(
             "toJavaScript", objType, objType));
     static final MethodReference fromJsMethod = new MethodReference(convCls, new MethodDescriptor(
-            "fromJavaScript", objType, objType));
+            "fromJavaScript", objType, objType, objType));
 
     @Override
     public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
@@ -53,43 +57,67 @@ public class JavaScriptConvGenerator implements Generator {
         String obj = context.getParameterName(1);
         writer.append("if (" + obj + " === null) {").softNewLine().indent();
         writer.append("return null;").softNewLine();
+        writer.outdent().append("} else if (typeof " + obj + " === 'number') {").indent().softNewLine();
+        writer.append("return " + obj + ";").softNewLine();
         writer.outdent().append("} else if (" + obj + ".constructor.$meta.item) {").indent().softNewLine();
         writer.append("var arr = new Array(" + obj + ".data.length);").softNewLine();
         writer.append("for (var i = 0; i < arr.length; ++i) {").indent().softNewLine();
         writer.append("arr[i] = ").appendMethodBody(toJsMethod).append("(" + obj + ".data[i]);").softNewLine();
         writer.outdent().append("}").softNewLine();
         writer.append("return arr;").softNewLine();
-        writer.outdent().append("}");
-        writer.append(" else if (" + obj + ".constructor === ").appendClass("java.lang.String")
+        writer.outdent().append("} else if (" + obj + ".constructor === ").appendClass("java.lang.String")
                 .append(") {").indent().softNewLine();
         generateStringToJavaScript(context, writer);
         writer.outdent().append("} else if (" + obj + ".constructor === ").appendClass("java.lang.Integer")
                 .append(") {").indent().softNewLine();
         writer.append("return ").appendMethodBody(intValueMethod).append("(" + obj + ");").softNewLine();
-        writer.outdent().append("}");
-        writer.append(" else {").indent().softNewLine();
+        writer.outdent().append("} else if (" + obj + ".constructor === ").appendClass("java.lang.Boolean")
+                .append(") {").indent().softNewLine();
+        writer.append("return ").appendMethodBody(booleanValueMethod).append("(" + obj + ")!==0;").softNewLine();
+        writer.outdent().append("} else {").indent().softNewLine();
         writer.append("return " + obj + ";").softNewLine();
         writer.outdent().append("}").softNewLine();
     }
 
     private void generateFromJavaScript(GeneratorContext context, SourceWriter writer) throws IOException {
         String obj = context.getParameterName(1);
+        String type = context.getParameterName(2);
         writer.append("if (" + obj +" === null || " + obj + " === undefined)").ws().append("{")
                 .softNewLine().indent();
         writer.append("return null;").softNewLine();
-        writer.outdent().append("} else if (" + obj + " instanceof Array) {").indent().softNewLine();
-        writer.append("var arr = $rt_createArray($rt_objcls(), " + obj + ".length);").softNewLine();
+        writer.outdent().append("} else if (" + type + ".$meta.item) {").indent().softNewLine();
+        writer.append("var arr = $rt_createArray(" + type + ".$meta.item, " + obj + ".length);").softNewLine();
         writer.append("for (var i = 0; i < arr.data.length; ++i) {").indent().softNewLine();
-        writer.append("arr.data[i] = ").appendMethodBody(fromJsMethod).append("(" + obj + "[i]);")
+        writer.append("arr.data[i] = ").appendMethodBody(fromJsMethod).append("(" + obj + "[i], " + type + ");")
                 .softNewLine();
         writer.outdent().append("}").softNewLine();
         writer.append("return arr;").softNewLine();
-        writer.outdent().append("}");
-        writer.append(" else if (" + obj + ".constructor === ").appendClass("java.lang.String")
+        writer.outdent().append("} else if (" + type + " === ").appendClass("java.lang.String")
                 .append(") {").indent().softNewLine();
         writer.append("return $rt_str(" + obj + ");").softNewLine();
-        writer.outdent().append("} else if (" + obj + " | 0 === " + obj + ") {").indent().softNewLine();
+        writer.outdent().append("} else if (" + type + " === ").appendClass("java.lang.Integer")
+                .append(") {").indent().softNewLine();
         writer.append("return ").appendMethodBody(valueOfIntMethod).append("(" + obj + ");").softNewLine();
+        writer.outdent().append("} else if (" + type + " === $rt_intcls()) {").indent().softNewLine();
+        writer.append("return " + obj + "|0;").softNewLine();
+        writer.outdent().append("} else if (" + type + " === ").appendClass("java.lang.Boolean")
+                .append(") {").indent().softNewLine();
+        writer.append("return ").appendMethodBody(valueOfBooleanMethod).append("(" + obj + "?1:0);").softNewLine();
+        writer.outdent().append("} else if (" + type + " === $rt_booleancls()) {").indent().softNewLine();
+        writer.append("return " + obj + "?1:0;").softNewLine();
+        writer.outdent().append("} else if (" + obj + " instanceof Array) {").indent().softNewLine();
+        writer.append("var arr = $rt_createArray($rt_objcls(), " + obj + ".length);").softNewLine();
+        writer.append("for (var i = 0; i < arr.data.length; ++i) {").indent().softNewLine();
+        writer.append("arr.data[i] = ").appendMethodBody(fromJsMethod).append("(" + obj + "[i], $rt_objcls());")
+                .softNewLine();
+        writer.outdent().append("}").softNewLine();
+        writer.append("return arr;").softNewLine();
+        writer.outdent().append("} else if (typeof " + obj + " === 'number') {").indent().softNewLine();
+        writer.append("if (" + obj + "|0 === " + obj + ") {").indent().softNewLine();
+        writer.append("return ").appendMethodBody(valueOfIntMethod).append("(" + obj + ");").softNewLine();
+        writer.outdent().append("}").softNewLine();
+        writer.outdent().append("} else if (typeof " + obj + " === 'boolean') {").indent().softNewLine();
+        writer.append("return ").appendMethodBody(valueOfBooleanMethod).append("(" + obj + "?1:0);").softNewLine();
         writer.outdent().append("} else {").indent().softNewLine();
         writer.append("return ").append(obj).append(";").softNewLine();
         writer.outdent().append("}").softNewLine();
diff --git a/teavm-html4j/src/test/java/org/teavm/html4j/test/JavaScriptBodyConversionTests.java b/teavm-html4j/src/test/java/org/teavm/html4j/test/JavaScriptBodyConversionTests.java
index a31e4b237..0cfaa1185 100644
--- a/teavm-html4j/src/test/java/org/teavm/html4j/test/JavaScriptBodyConversionTests.java
+++ b/teavm-html4j/src/test/java/org/teavm/html4j/test/JavaScriptBodyConversionTests.java
@@ -27,15 +27,30 @@ public class JavaScriptBodyConversionTests {
     @Test
     public void convertsInteger() {
         assertEquals(23, returnAsInt(23));
+        assertEquals(Integer.valueOf(23), returnAsInteger(23));
+        assertEquals(23, returnAsObject(23));
+        assertEquals(24, addOne((Object)23));
+        assertEquals(Integer.valueOf(24), addOne(Integer.valueOf(23)));
+        assertEquals(24, addOne(23));
     }
 
     @Test
     public void convertsIntegerResult() {
         assertEquals(23, returnAsObject(23));
+        assertEquals(Integer.valueOf(23), returnAsInteger(23));
+        assertEquals(23, returnAsInt(23));
+    }
+
+    @Test
+    public void convertsBoolean() {
+        assertTrue(returnAsBoolean(true));
+        assertTrue(returnAsBooleanWrapper(true));
+        assertEquals(Boolean.TRUE, returnAsObject(true));
     }
 
     @Test
     public void convertsArray() {
+        assertEquals(42, getArrayItem(new int[] { 23, 42 }, 1));
         assertEquals(42, getArrayItem(new Integer[] { 23, 42 }, 1));
     }
 
@@ -47,12 +62,46 @@ public class JavaScriptBodyConversionTests {
         assertEquals(Integer.valueOf(1), arrayCopy[0]);
     }
 
+    @Test
+    public void createsArrayOfProperType() {
+        assertEquals(Object[].class, returnAsObject(new int[] { 23, 42 }).getClass());
+        assertEquals(Integer[].class, returnAsIntegerArray(new Integer[] { 23, 42 }).getClass());
+        assertEquals(int[].class, returnAsIntArray(new Integer[] { 23, 42 }).getClass());
+    }
+
     @JavaScriptBody(args = { "value" }, body = "return value;")
     private native int returnAsInt(Object value);
 
+    @JavaScriptBody(args = { "value" }, body = "return value;")
+    private native boolean returnAsBoolean(Object value);
+
+    @JavaScriptBody(args = { "value" }, body = "return value;")
+    private native Boolean returnAsBooleanWrapper(boolean value);
+
+    @JavaScriptBody(args = { "value" }, body = "return value;")
+    private native Integer returnAsInteger(Integer value);
+
     @JavaScriptBody(args = { "value" }, body = "return value;")
     private native Object returnAsObject(int value);
 
+    @JavaScriptBody(args = { "value" }, body = "return value + 1;")
+    private native int addOne(Object value);
+
+    @JavaScriptBody(args = { "value" }, body = "return value + 1;")
+    private native Integer addOne(Integer value);
+
+    @JavaScriptBody(args = { "value" }, body = "return value + 1;")
+    private native int addOne(int value);
+
+    @JavaScriptBody(args = { "value" }, body = "return value;")
+    private native Object returnAsObject(Object array);
+
+    @JavaScriptBody(args = { "value" }, body = "return value;")
+    private native int[] returnAsIntArray(Object array);
+
+    @JavaScriptBody(args = { "value" }, body = "return value;")
+    private native Integer[] returnAsIntegerArray(Object array);
+
     @JavaScriptBody(args = { "value" }, body = "value[0] = 1; return value;")
     private native Object modifyIntegerArray(Object value);