diff --git a/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TTimeZone.java b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TTimeZone.java
index c1b5051a2..d67dc73d7 100644
--- a/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TTimeZone.java
+++ b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TTimeZone.java
@@ -15,6 +15,8 @@
  */
 package org.teavm.classlib.java.util;
 
+import org.teavm.jso.JSBody;
+
 /**
  * TimeZone represents a time zone offset, and also figures out daylight savings.
  * Typically, you get a TimeZone using getDefault which creates a TimeZone based on the time zone where the program is running. For example, for a program running in Japan, getDefault creates a TimeZone object based on Japanese Standard Time.
@@ -62,10 +64,20 @@ public abstract class TTimeZone {
             return new String[] {"GMT", i};
         }
     }
-
+    @JSBody(params={}, 
+            script="return $rt_getTimezoneId(name,year,month,day,timeOfDayMillis)"
+            )
     private static native String getTimezoneId();
+    
+    @JSBody(params={"name","year","month","day","timeOfDayMillis"},
+            script="return $rt_getTimezoneOffset(name,year,month,day,timeOfDayMillis)")
     private static native int getTimezoneOffset(String name, int year, int month, int day, int timeOfDayMillis);
+    
+    @JSBody(params="name",
+            script="return $rt_getTimezoneRawOffset(name)")
     private static native int getTimezoneRawOffset(String name);
+    
+    @JSBody(params={"name","millis"}, script="return $rt_isTimezoneDST(name,millis)")
     private static native boolean isTimezoneDST(String name, long millis);
 
     /**
diff --git a/teavm-core/src/main/resources/org/teavm/javascript/runtime.js b/teavm-core/src/main/resources/org/teavm/javascript/runtime.js
index 142d1cc95..dff1691cc 100644
--- a/teavm-core/src/main/resources/org/teavm/javascript/runtime.js
+++ b/teavm-core/src/main/resources/org/teavm/javascript/runtime.js
@@ -529,7 +529,49 @@ function $rt_nativeThread() {
 function $rt_invalidPointer() {
     throw new Error("Invalid recorded state");
 }
-
+function $rt_getTimezoneId(){
+    return "LOCAL";
+}
+function $rt_getTimezoneOffset(name, year, month, day, timeOfDayMillis){
+    if ($rt_getTimezoneId()===name){
+        var hours = Math.floor(timeOfDayMillis/1000/60/60);
+        var minutes = Math.floor(timeOfDayMillis/1000/60)%60;
+        var seconds = Math.floor(timeOfDayMillis/1000)%60;
+        var millis = timeOfDayMillis % 1000;
+        return -(new Date(year, month, day, hours, minutes, seconds, millis).getTimezoneOffset()*1000*60);
+    } else if ("UTC"===name || "GMT"===name){
+        return 0;
+    } else {
+        throw new Error("Unsupported Timezone: "+name);
+    }
+}
+function $rt_getTimezoneRawOffset(name){
+    if ($rt_getTimezoneId()===name){
+        var millis = new Date().getTime();
+        var i=0;
+        var addDays = 1000 * 60 *60 * 24 * 200; // Check 200 days later
+        while ($rt_isTimezoneDST(name, millis) && i++<4){
+            millis += addDays;
+        }
+        return -(new Date(millis).getTimezoneOffset()*1000*60);
+    } else if (name==='GMT' || name==='UTC'){
+        return 0;
+    } else {
+        throw new Error("Unsupported Timezone: "+name);
+    }
+}
+function $rt_isTimezoneDST(name, millis){
+    if ($rt_getTimezoneId()===name){
+        var jan = new Date(this.getFullYear(), 0, 1);
+        var jul = new Date(this.getFullYear(), 6, 1);
+        var maxOff = Math.max(jan.getTimezoneOffset(), jul.getTimezoneOffset());
+        return new Date(millis).getTimezoneOffset()<maxOff;
+    } else if (name==='GMT' || name=='UTC'){
+        return false;
+    } else {
+        throw new Error("Unsupported Timezone: "+name);
+    }
+}
 function $dbg_repr(obj) {
     return obj.toString ? obj.toString() : "";
 }
diff --git a/teavm-tests/src/test/java/org/teavm/classlib/java/text/DateFormatTest.java b/teavm-tests/src/test/java/org/teavm/classlib/java/text/DateFormatTest.java
index 30576e590..bc00f831a 100644
--- a/teavm-tests/src/test/java/org/teavm/classlib/java/text/DateFormatTest.java
+++ b/teavm-tests/src/test/java/org/teavm/classlib/java/text/DateFormatTest.java
@@ -60,13 +60,13 @@ public class DateFormatTest {
     private Date getDateWithZoneOffset(long milliseconds) {
         Calendar calendar = new GregorianCalendar(Locale.ENGLISH);
         calendar.setTimeInMillis(milliseconds);
-        milliseconds -= calendar.get(Calendar.ZONE_OFFSET);
+        milliseconds -= calendar.get(Calendar.ZONE_OFFSET)-calendar.get(Calendar.DST_OFFSET);
         return new Date(milliseconds);
     }
 
     private long getTimeWithoutZoneOffset(Date date) {
         Calendar calendar = new GregorianCalendar(Locale.ENGLISH);
         calendar.setTime(date);
-        return calendar.getTimeInMillis() + calendar.get(Calendar.ZONE_OFFSET);
+        return calendar.getTimeInMillis() + calendar.get(Calendar.ZONE_OFFSET)+calendar.get(Calendar.DST_OFFSET);
     }
 }
diff --git a/teavm-tests/src/test/java/org/teavm/classlib/java/text/SimpleDateFormatTest.java b/teavm-tests/src/test/java/org/teavm/classlib/java/text/SimpleDateFormatTest.java
index f5ce9d4ae..8a87fec0b 100644
--- a/teavm-tests/src/test/java/org/teavm/classlib/java/text/SimpleDateFormatTest.java
+++ b/teavm-tests/src/test/java/org/teavm/classlib/java/text/SimpleDateFormatTest.java
@@ -137,12 +137,13 @@ public class SimpleDateFormatTest {
         Calendar calendar = new GregorianCalendar(Locale.ENGLISH);
         calendar.setTimeInMillis(milliseconds);
         milliseconds -= calendar.get(Calendar.ZONE_OFFSET);
+        milliseconds -= calendar.get(Calendar.DST_OFFSET);
         return new Date(milliseconds);
     }
 
     private long getTimeWithoutZoneOffset(Date date) {
         Calendar calendar = new GregorianCalendar(Locale.ENGLISH);
         calendar.setTime(date);
-        return calendar.getTimeInMillis() + calendar.get(Calendar.ZONE_OFFSET);
+        return calendar.getTimeInMillis() + calendar.get(Calendar.ZONE_OFFSET) + calendar.get(Calendar.DST_OFFSET);
     }
 }
diff --git a/teavm-tests/src/test/java/org/teavm/classlib/java/util/TimeZoneTest.java b/teavm-tests/src/test/java/org/teavm/classlib/java/util/TimeZoneTest.java
new file mode 100644
index 000000000..0bbf4e899
--- /dev/null
+++ b/teavm-tests/src/test/java/org/teavm/classlib/java/util/TimeZoneTest.java
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2015 shannah.
+ *
+ * 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.classlib.java.util;
+
+/**
+ *
+ * @author shannah
+ */
+public class TimeZoneTest {
+    
+}