diff --git a/teavm-jso/src/main/java/org/teavm/jso/core/JSRegExp.java b/teavm-jso/src/main/java/org/teavm/jso/core/JSRegExp.java
new file mode 100644
index 000000000..d30a7a88a
--- /dev/null
+++ b/teavm-jso/src/main/java/org/teavm/jso/core/JSRegExp.java
@@ -0,0 +1,83 @@
+/*
+ *  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.core;
+
+import org.teavm.jso.JSBody;
+import org.teavm.jso.JSObject;
+import org.teavm.jso.JSProperty;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+public abstract class JSRegExp implements JSObject {
+    @JSBody(params = "pattern", script = "return new RegExp(pattern);")
+    public static native JSRegExp create(String pattern);
+
+    @JSBody(params = { "pattern", "flags" }, script = "return new RegExp(pattern, flags);")
+    public static native JSRegExp create(String pattern, String flags);
+
+    public static JSRegExp create(String pattern, JSRegExpFlag... flags) {
+        boolean global = false;
+        boolean ignoreCase = false;
+        boolean multiline = false;
+        for (JSRegExpFlag flag : flags) {
+            switch (flag) {
+                case GLOBAL:
+                    global = true;
+                    break;
+                case IGNORE_CASE:
+                    ignoreCase = true;
+                    break;
+                case MULTILINE:
+                    multiline = true;
+                    break;
+            }
+        }
+        StringBuilder sb = new StringBuilder();
+        if (global) {
+            sb.append('g');
+        }
+        if (ignoreCase) {
+            sb.append('i');
+        }
+        if (multiline) {
+            sb.append('m');
+        }
+        return create(pattern, sb.toString());
+    }
+
+    @JSProperty
+    public abstract boolean isGlobal();
+
+    @JSProperty
+    public abstract boolean isIgnoreCase();
+
+    @JSProperty
+    public abstract boolean isMultiline();
+
+    @JSProperty
+    public abstract int getLastIndex();
+
+    @JSProperty
+    public abstract JSString getSource();
+
+    public abstract JSArray<JSString> exec(JSString text);
+
+    public abstract boolean test(JSString text);
+
+    public abstract boolean test(String text);
+}
diff --git a/teavm-jso/src/main/java/org/teavm/jso/core/JSRegExpFlag.java b/teavm-jso/src/main/java/org/teavm/jso/core/JSRegExpFlag.java
new file mode 100644
index 000000000..3306f06a1
--- /dev/null
+++ b/teavm-jso/src/main/java/org/teavm/jso/core/JSRegExpFlag.java
@@ -0,0 +1,26 @@
+/*
+ *  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.core;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+public enum JSRegExpFlag {
+    GLOBAL,
+    IGNORE_CASE,
+    MULTILINE
+}
diff --git a/teavm-jso/src/main/java/org/teavm/jso/core/JSReplaceFunction.java b/teavm-jso/src/main/java/org/teavm/jso/core/JSReplaceFunction.java
new file mode 100644
index 000000000..ecedc544b
--- /dev/null
+++ b/teavm-jso/src/main/java/org/teavm/jso/core/JSReplaceFunction.java
@@ -0,0 +1,28 @@
+/*
+ *  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.core;
+
+import org.teavm.jso.JSFunctor;
+import org.teavm.jso.JSObject;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+@JSFunctor
+public interface JSReplaceFunction extends JSObject {
+    String apply(String matched);
+}
diff --git a/teavm-jso/src/main/java/org/teavm/jso/core/JSString.java b/teavm-jso/src/main/java/org/teavm/jso/core/JSString.java
index 1e240be24..da4446f50 100644
--- a/teavm-jso/src/main/java/org/teavm/jso/core/JSString.java
+++ b/teavm-jso/src/main/java/org/teavm/jso/core/JSString.java
@@ -57,12 +57,32 @@ public abstract class JSString implements JSObject {
 
     public abstract int lastIndexOf(JSString a);
 
+    public abstract JSArray<JSString> match(JSRegExp regexp);
+
+    public abstract JSArray<JSString> match(JSString regexp);
+
+    public abstract JSString replace(JSRegExp regexp, JSString replaceBy);
+
+    public abstract JSString replace(JSRegExp regexp, JSReplaceFunction replaceBy);
+
+    public abstract JSString replace(JSString regexp, JSString replaceBy);
+
+    public abstract JSString replace(JSString regexp, JSReplaceFunction replaceBy);
+
+    public abstract int search(JSRegExp regexp);
+
+    public abstract int search(JSString regexp);
+
     public abstract JSString slice(int beginSlice);
 
     public abstract JSString slice(int beginSlice, int endSlice);
 
+    public abstract JSString[] split(JSRegExp separator);
+
     public abstract JSString[] split(JSString separator);
 
+    public abstract JSString[] split(JSRegExp separator, int limit);
+
     public abstract JSString[] split(JSString separator, int limit);
 
     public abstract JSString substr(int start);
@@ -73,6 +93,12 @@ public abstract class JSString implements JSObject {
 
     public abstract JSString substring(int start, int end);
 
+    public abstract JSString toLowerCase();
+
+    public abstract JSString toUpperCase();
+
+    public abstract JSString trim();
+
     @JSBody(params = "obj", script = "return typeof this === 'string';")
     public static native boolean isInstance(JSObject obj);
 }