diff --git a/test/js2tests/stringprototype.py b/test/js2tests/stringprototype.py
new file mode 100644
index 000000000..531fcc211
--- /dev/null
+++ b/test/js2tests/stringprototype.py
@@ -0,0 +1,12 @@
+from __future__ import unicode_literals
+
+skip = {'parse': 'Ast not yet implemented'}
+
+tests = [
+    {
+        'code': '"hello".split("");',
+        'globals': {},
+        'asserts': [{'value': ['h', 'e', 'l', 'l', 'o']}],
+        'ast': []
+    }
+]
diff --git a/youtube_dl/jsinterp2/jsbuilt_ins/__init__.py b/youtube_dl/jsinterp2/jsbuilt_ins/__init__.py
new file mode 100644
index 000000000..b87d1a03d
--- /dev/null
+++ b/youtube_dl/jsinterp2/jsbuilt_ins/__init__.py
@@ -0,0 +1,57 @@
+from __future__ import unicode_literals
+
+from . import base
+from . import jsobject
+from . import jsfunction
+from . import jsarray
+from . import jsboolean
+from . import jsstring
+from . import jsnumber
+
+from .base import null, undefined
+from .jsboolean import false, true
+
+
+def _eval(code):
+    pass
+
+
+def _parse_int(string, radix):
+    pass
+
+
+def _parse_float(string):
+    pass
+
+
+def _is_nan(number):
+    pass
+
+
+def _is_infinite(number):
+    pass
+
+
+def _decode_uri(encoded_uri):
+    pass
+
+
+def _decode_uri_component(encoded_uri_component):
+    pass
+
+
+def _encode_uri(uri):
+    pass
+
+
+def _encode_uri_component(uri_component):
+    pass
+
+
+global_obj = jsobject.JSObject.construct(
+    {'Object': jsobject.JSObject(),
+     'Array': jsarray.JSArray(),
+     'Function': jsfunction.JSFunction(),
+     'String': jsstring.JSString(),
+     'Number': jsnumber.JSNumber()
+     })
diff --git a/youtube_dl/jsinterp2/jsbuilt_ins/base.py b/youtube_dl/jsinterp2/jsbuilt_ins/base.py
new file mode 100644
index 000000000..2e63a958d
--- /dev/null
+++ b/youtube_dl/jsinterp2/jsbuilt_ins/base.py
@@ -0,0 +1,65 @@
+from __future__ import unicode_literals
+
+from types import FunctionType
+
+from ...compat import compat_str
+
+
+class JSBase(object):
+
+    def __init__(self, name):
+        self.name = name
+        self.props = {}
+
+    own = {}
+
+
+undefined = JSBase('undefined')
+null = JSBase('null')
+
+
+class JSProtoBase(JSBase):
+
+    def __init__(self):
+        super(JSProtoBase, self).__init__('')
+        cls = self.__class__
+        while cls.__base__ is not JSProtoBase:
+            cls = cls.__base__
+            props = cls.own.copy()
+            props.update(self.props)
+            self.props = props
+        self.value = {}
+
+    def get_prop(self, prop):
+        result = self.value.get(prop) if hasattr(self.value, 'get') else None
+        if result is None:
+            result = self.own.get(prop)
+        if result is None:
+            result = self.props.get(prop)
+        return result
+
+    def call_prop(self, prop, *args, **kwargs):
+        func = self.get_prop(prop)
+        if isinstance(func, native_function):
+            return func(self, *args, **kwargs)
+        elif isinstance(func, staticmethod):
+            return func.__func__(*args, **kwargs)
+        elif isinstance(func, classmethod):
+            return func.__func__(self.__class__, *args, **kwargs)
+        elif isinstance(func, JSBase) and hasattr(func, 'call'):
+            return func.call(*args, **kwargs)
+        else:
+            # FIXME instead of prop should return the whole expression
+            # needs to use internal exception
+            # interpreter should raise JSTypeError
+            raise Exception('TypeError: %s is not a function' % prop)
+
+    jsclass = ''
+
+
+native_bool = bool
+native_string = compat_str
+native_number = (int, float)
+native_object = dict
+native_array = (list, tuple)
+native_function = FunctionType
diff --git a/youtube_dl/jsinterp2/jsbuilt_ins/internals.py b/youtube_dl/jsinterp2/jsbuilt_ins/internals.py
new file mode 100644
index 000000000..e822d87fc
--- /dev/null
+++ b/youtube_dl/jsinterp2/jsbuilt_ins/internals.py
@@ -0,0 +1,222 @@
+from __future__ import unicode_literals
+
+import re
+from math import isnan, isinf, log10
+from sys import float_info
+
+from .base import native_bool, native_string, native_number, native_object
+from .utils import to_js
+from ..jsgrammar import __HEXADECIMAL_RE
+
+undefined_type = object()
+null_type = object()
+boolean_type = object()
+string_type = object()
+number_type = object()
+object_type = object()
+
+
+def jstype(o):
+    from .base import null, undefined
+    from .jsboolean import true, false
+
+    if o is undefined:
+        return undefined_type
+    elif o is None or o is null:
+        return null_type
+    elif isinstance(o, native_bool) or o is true or o is false:
+        return boolean_type
+    elif isinstance(o, native_string):
+        return string_type
+    elif isinstance(o, native_number):
+        return number_type
+    elif isinstance(o, native_object):
+        return object_type
+    return None
+
+
+def to_primitive(o, hint=None):
+    # TODO to_primitive
+    return o
+
+
+def to_boolean(o):
+    from .base import undefined, null
+    from .jsobject import JSObjectPrototype
+    from .jsboolean import JSBooleanPrototype, false, true
+    from .jsstring import JSStringPrototype
+    from .jsnumber import JSNumberPrototype
+
+    if o is undefined or o is null:
+        return false
+    elif isinstance(o, JSBooleanPrototype):
+        return o.value
+    elif isinstance(o, JSNumberPrototype):
+        return true if o.value and not isnan(o.value) else false
+    elif isinstance(o, JSStringPrototype):
+        return true if o.value else false
+    elif isinstance(o, JSObjectPrototype):
+        return true
+    else:
+        raise Exception('Failed to convert type %s to Boolean (not specified)' % type(o))
+
+
+def to_number(o):
+    from .base import null, undefined
+    from .jsobject import JSObjectPrototype
+    from .jsboolean import JSBooleanPrototype, false, true
+    from .jsstring import JSStringPrototype
+
+    if o is undefined:
+        return float('nan')
+    elif o is null or isinstance(o, JSBooleanPrototype) and o.value is false:
+        return 0
+    elif isinstance(o, JSBooleanPrototype) and o.value is true:
+        return 1
+    elif isinstance(o, JSStringPrototype):
+        _STR_FLOAT_RE = r'(?:(?:[0-9]+(?:\.[0-9]*)?)|(?:\.[0-9]+))(?:[eE][+-]?[0-9]+)?'
+        m = re.match(r'^[\s\n]*(?P<value>(?:[+-]*(?:Infinity|%(float)s))|%(hex)s)?[\s\n]*$' % {'float': _STR_FLOAT_RE,
+                                                                                               'hex': __HEXADECIMAL_RE},
+                     o.value)
+        if m:
+            v = m.group('value')
+            if v:
+                s = 1 if v.startswith('+') or v.startswith('-') else 0
+                if v[s:] == 'Infinity':
+                    return float(v[:s] + 'inf')  # 10 ** 10000 according to spec
+                elif v[s:].isdigit():
+                    return int(v)
+                elif v.startswith('0x') or v.startswith('0X'):
+                    return int(v, 16)
+                else:
+                    return float(v)
+            else:
+                return 0
+        else:
+            return float('nan')
+
+    elif isinstance(o, JSObjectPrototype):
+        prim_value = to_primitive(o, 'Number')
+        return to_number(prim_value)
+    else:
+        raise Exception('Failed to convert type %s to Number (not specified)' % type(o))
+
+
+def to_integer(o):
+    number = to_number(o)
+    if isnan(number):
+        return 0
+    elif isinf(number) or number == 0:
+        return number
+    return int(number)  # equivalent to: int(copysign(floor(abs(number)), number))
+
+
+def to_int32(o):
+    number = to_number(o)
+    if isnan(number) or isinf(number) or number == 0:
+        return 0
+    pos_int = int(number)
+    int32 = pos_int % 2 ** 32
+    return int32 if int32 < 2 ** 31 else int32 - 2 ** 32
+
+
+def to_uint32(o):
+    number = to_number(o)
+    if isnan(number) or isinf(number) or number == 0:
+        return 0
+    pos_int = int(number)
+    int32 = pos_int % 2 ** 32
+    return int32
+
+
+def to_uint16(o):
+    number = to_number(o)
+    if isnan(number) or isinf(number) or number == 0:
+        return 0
+    pos_int = int(number)
+    int16 = pos_int % 2 ** 16
+    return int16
+
+
+def to_string(o):
+    from .base import null, undefined
+    from .jsobject import JSObjectPrototype
+    from .jsboolean import JSBooleanPrototype, false, true
+    from .jsnumber import JSNumberPrototype
+
+    if o is undefined:
+        return 'undefined'
+    elif o is null:
+        return 'null'
+    elif isinstance(o, JSBooleanPrototype):
+        if o is true:
+            return 'true'
+        elif o is false:
+            return 'false'
+    elif isinstance(o, JSNumberPrototype):
+        ov = o.value
+        if isnan(ov):
+            return 'NaN'
+        elif ov == 0.0:
+            return '0'
+        elif ov < 0:
+            return '-' + to_string(to_js(-ov))
+        elif isinf(ov):
+            return 'Infinity'
+        else:
+            # numerically unstable example: 3333330000000000000.3 or 3.3333300000000000003e+20
+            n = log10(ov) + 1
+            n = int(n)
+            k = 1
+
+            while True:
+                exp = 10 ** (k - n)
+                s = int(ov * exp)
+                if abs(ov * exp - s) < float_info.epsilon:
+                    break
+                k += 1
+
+            if s % 10 == 0:
+                s //= 10
+            m = '%d' % s
+
+            if k <= n <= 21:
+                return m[:k] + '0' * (n - k)
+            elif 0 < n <= 21:
+                return m[:n] + '.' + m[n:k]
+            elif -6 < n <= 0:
+                return '0.' + '0' * -n + m[:k]
+            elif k == 1:
+                return m[0] + 'e%+d' % (n - 1)
+            else:
+                return m[0] + '.' + m[:k] + 'e%+d' % (n - 1)
+
+    elif isinstance(o, JSObjectPrototype):
+        prim_value = to_primitive(o, 'String')
+        return to_string(prim_value)
+    else:
+        raise Exception('Failed to convert type %s to String (not specified)' % type(o))
+
+
+def to_object(o):
+    from .base import null, undefined
+    from .jsobject import JSObjectPrototype
+    from .jsboolean import JSBooleanPrototype
+    from .jsstring import JSStringPrototype
+    from .jsnumber import JSNumberPrototype
+
+    if o is undefined or o is null:
+        raise Exception('TypeError: Cannot convert undefined or null to object')
+    elif isinstance(o, JSBooleanPrototype):
+        return JSBooleanPrototype(o)
+    elif isinstance(o, JSNumberPrototype):
+        return JSNumberPrototype(o)
+    elif isinstance(o, JSStringPrototype):
+        return JSStringPrototype(o)
+    elif isinstance(o, JSObjectPrototype):
+        return o
+
+
+def throw_type_error():
+    # TODO [[ThrowTypeError]] (13.2.3)
+    pass
diff --git a/youtube_dl/jsinterp2/jsbuilt_ins/jsarray.py b/youtube_dl/jsinterp2/jsbuilt_ins/jsarray.py
new file mode 100644
index 000000000..f6c329f3f
--- /dev/null
+++ b/youtube_dl/jsinterp2/jsbuilt_ins/jsarray.py
@@ -0,0 +1,153 @@
+from __future__ import unicode_literals
+
+from .base import native_number, undefined
+from .jsobject import JSObject, JSObjectPrototype
+from .jsnumber import JSNumberPrototype
+
+
+class JSArrayPrototype(JSObjectPrototype):
+
+    def __init__(self, value=None):
+        super(JSArrayPrototype, self).__init__()
+        if value is None:
+            # prototype
+            self.value = []
+        else:
+            self.value = value
+            self.own = dict((str(i), v) for i, v in enumerate(value))
+            self.own['length'] = self._length
+
+    def __str__(self):
+        return 'JSArrayPrototype: %s' % self.value
+
+    def __repr__(self):
+        return 'JSArrayPrototype(%s, %s)' % (self.value, self._length)
+
+    @property
+    def _length(self):
+        return len(self.value)
+
+    @staticmethod
+    def _constructor(*args):
+        return JSArray.construct(*args)
+
+    def _to_string(self):
+        return 'array to string'
+
+    def _to_locale_string(self):
+        return 'array to locale string'
+
+    def _concat(self, *items):
+        return 'array concat'
+
+    def _join(self, sep):
+        return 'array join'
+
+    def _pop(self):
+        return 'array pop'
+
+    def _push(self, *items):
+        return 'array push'
+
+    def _reverse(self):
+        return 'array reverse'
+
+    def _shift(self):
+        return 'array shift'
+
+    def _slice(self, start, end):
+        return 'array slice'
+
+    def _sort(self, cmp):
+        return 'array sort'
+
+    def _splice(self, start, delete_count, *items):
+        return 'array splice'
+
+    def _unshift(self, *items):
+        return 'array unshift'
+
+    def _index_of(self, elem, from_index=0):
+        return 'array index of'
+
+    def _last_index_of(self, elem, from_index=None):
+        if from_index is None:
+            from_index = len(self.value) - 1
+        return 'array index of'
+
+    def _every(self, callback, this_arg=None):
+        return 'array every'
+
+    def _some(self, callback, this_arg=None):
+        return 'array some'
+
+    def _for_each(self, callback, this_arg=None):
+        return 'array for_each'
+
+    def _map(self, callback, this_arg=None):
+        return 'array map'
+
+    def _filter(self, callback, this_arg=None):
+        return 'array filter'
+
+    def _reduce(self, callback, init=None):
+        return 'array reduce'
+
+    def _reduce_right(self, callback, init=None):
+        return 'array reduce right'
+
+    jsclass = 'Array'
+    own = {
+        'length': _length,
+        'constructor': _constructor,
+        'toString': _to_string,
+        'toLocaleString': _to_locale_string,
+        'concat': _concat,
+        'join': _join,
+        'pop': _pop,
+        'push': _push,
+        'reverse': _reverse,
+        'shift': _shift,
+        'slice': _slice,
+        'sort': _sort,
+        'splice': _splice,
+        'unshift': _unshift,
+        'indexOf': _index_of,
+        'lastIndexOf': _last_index_of,
+        'every': _every,
+        'some': _some,
+        'forEach': _for_each,
+        'map': _map,
+        'filter': _filter,
+        'reduce': _reduce,
+        'reduceRight': _reduce_right
+    }
+
+
+class JSArray(JSObject):
+
+    @staticmethod
+    def call(*args):
+        return JSArray.construct(*args)
+
+    @staticmethod
+    def construct(*args):
+        if len(args) == 1:
+            if isinstance(args[0], native_number):
+                return JSArrayPrototype([undefined] * args[0])
+            elif isinstance(args[0], JSNumberPrototype):
+                return JSArrayPrototype([undefined] * args[0]._value_of())
+        if args:
+            return JSArrayPrototype(args)
+        else:
+            return JSArrayPrototype([])
+
+    def _is_array(self, arg):
+        return 'array is array'
+
+    name = JSArrayPrototype.jsclass
+    own = {
+        'length': 1,
+        'prototype': JSArrayPrototype(),
+        'isArray': _is_array
+    }
diff --git a/youtube_dl/jsinterp2/jsbuilt_ins/jsboolean.py b/youtube_dl/jsinterp2/jsbuilt_ins/jsboolean.py
new file mode 100644
index 000000000..ad3895815
--- /dev/null
+++ b/youtube_dl/jsinterp2/jsbuilt_ins/jsboolean.py
@@ -0,0 +1,62 @@
+from __future__ import unicode_literals
+
+from .internals import jstype, boolean_type, object_type, to_boolean
+from .utils import to_js
+from .jsobject import JSObject, JSObjectPrototype
+
+
+class JSBooleanPrototype(JSObjectPrototype):
+
+    def __init__(self, value=None):
+        super(JSBooleanPrototype, self).__init__()
+        if value is None:
+            # prototype
+            value = False
+        else:
+            self.value = value
+            self.own = {}
+
+    @staticmethod
+    def _constructor(value=None):
+        return JSBoolean.construct(value)
+
+    def _to_string(self):
+        # TODO find way to test it in other interpreters
+        if jstype(self) is boolean_type:
+            b = self
+        elif jstype(self) is object_type and self.jsclass == 'Boolean':
+            b = self.value
+        else:
+            raise Exception('TypeError')
+        return 'true' if b is true else 'false'
+
+    def _value_of(self):
+        return 'boolean value of'
+
+    jsclass = 'Boolean'
+    own = {
+        'constructor': _constructor,
+        'toString': _to_string,
+        'valueOf': _value_of
+    }
+
+
+true = JSBooleanPrototype(True)
+false = JSBooleanPrototype(False)
+
+
+class JSBoolean(JSObject):
+
+    @staticmethod
+    def call(value=None):
+        return to_boolean(to_js(value))
+
+    @staticmethod
+    def construct(value=None):
+        return JSBooleanPrototype(to_boolean(to_js(value)))
+
+    name = JSBooleanPrototype.jsclass
+    own = {
+        'length': 1,
+        'prototype': JSBooleanPrototype()
+    }
diff --git a/youtube_dl/jsinterp2/jsbuilt_ins/jsfunction.py b/youtube_dl/jsinterp2/jsbuilt_ins/jsfunction.py
new file mode 100644
index 000000000..6deb6f4b5
--- /dev/null
+++ b/youtube_dl/jsinterp2/jsbuilt_ins/jsfunction.py
@@ -0,0 +1,110 @@
+from __future__ import unicode_literals
+
+from .base import undefined, null
+from .internals import to_string, throw_type_error
+from .base import native_function, JSBase
+from .utils import to_js
+from .jsobject import JSObject, JSObjectPrototype
+
+
+class JSFunctionPrototype(JSObjectPrototype):
+
+    def __init__(self, name, body, formal_args):
+        if name is None and body is None and formal_args is None:
+            # prototype
+            super(JSFunctionPrototype, self).__init__()
+            self.f_name = ''
+            self.body = ''
+        else:
+            if isinstance(body, JSBase):
+                super(JSFunctionPrototype, self).__init__(body.own)
+                self.body = '[native code]'
+            elif isinstance(body, native_function):
+                super(JSFunctionPrototype, self).__init__()
+                self.body = '[native code]'
+            else:
+                super(JSFunctionPrototype, self).__init__()
+                body = to_js(body)
+                self.body = to_string(body) if body is not undefined or body is not null else ''
+            self.f_name = name
+            self.arguments = list(formal_args)
+            proto = JSObject.construct()
+            proto.own['constructor'] = self
+            self.own = {'length': self._length,
+                        'prototype': proto
+                        }
+            # TODO Handle strict mode
+            strict = True
+            if strict:
+                thrower = throw_type_error
+                self.own['caller'] = thrower
+                self.own['arguments'] = thrower
+            # FIXME: JSProtoBase sets body to '' instead of None
+            # TODO check if self._args can be parsed as formal parameter list
+            # TODO check if self._body can be parsed as function body
+            # TODO set strict
+            # TODO throw strict mode exceptions
+            # (double argument, "eval" or "arguments" in arguments, function identifier is "eval" or "arguments")
+
+    @property
+    def _length(self):
+        return len(self.arguments)
+
+    @staticmethod
+    def _constructor(arguments=None):
+        return JSFunction.construct(arguments)
+
+    def _to_string(self):
+        if self.body is not None:
+            body = '\n'
+            body += '\t' + self.body if self.body else self.body
+        else:
+            body = ''
+        return 'function %s(%s) {%s\n}' % (
+            self.f_name,
+            ', '.join(self.arguments),
+            body)
+
+    def _apply(self, this_arg, arg_array):
+        return 'function apply'
+
+    def _call(self, this_arg, *args):
+        return 'function call'
+
+    def _bind(self, this_arg, *args):
+        return 'function bind'
+
+    jsclass = 'Function'
+    own = {
+        'length': 0,
+        'constructor': _constructor,
+        'toString': _to_string,
+        'apply': _apply,
+        'call': _call,
+        'bind': _bind
+    }
+
+
+class JSFunction(JSObject):
+
+    @staticmethod
+    def call(formal_args=None):
+        return JSFunction.construct(formal_args)
+
+    @staticmethod
+    def construct(formal_args=None):
+        if formal_args is not None and formal_args:
+            body = formal_args[-1]
+            formal_args = []
+            for arg in formal_args[:-1]:
+                formal_args.extend(a.strip() for a in arg.split(','))
+        else:
+            body = ''
+            formal_args = []
+        return JSFunctionPrototype('anonymous', body, formal_args)
+
+    name = JSFunctionPrototype.jsclass
+    own = {
+        'length': 1,
+        'prototype': JSFunctionPrototype(None, None, None)
+    }
diff --git a/youtube_dl/jsinterp2/jsbuilt_ins/jsnumber.py b/youtube_dl/jsinterp2/jsbuilt_ins/jsnumber.py
new file mode 100644
index 000000000..e2f195c92
--- /dev/null
+++ b/youtube_dl/jsinterp2/jsbuilt_ins/jsnumber.py
@@ -0,0 +1,74 @@
+from __future__ import unicode_literals
+
+from .internals import jstype, number_type, to_number
+from .utils import to_js
+from .jsobject import JSObject, JSObjectPrototype
+
+
+class JSNumberPrototype(JSObjectPrototype):
+
+    def __init__(self, value=None):
+        super(JSNumberPrototype, self).__init__()
+        if value is None:
+            # prototype
+            value = 0
+        else:
+            self.value = value
+            self.own = {}
+
+    @staticmethod
+    def _constructor(value=None):
+        return JSNumber.construct(value)
+
+    def _to_string(self, radix=None):
+        pass
+
+    def _to_locale_string(self):
+        pass
+
+    def _value_of(self):
+        if jstype(self.value) is not number_type or isinstance(self.value, JSNumberPrototype):
+            # TODO find way to test it in other interpreters
+            raise Exception('TypeError')
+        return self.value
+
+    def _to_fixed(self, frac_digits):
+        return 'Number toFixed'
+
+    def _to_exponential(self, frac_digits):
+        return 'Number toExponential'
+
+    def _to_precision(self, prec):
+        return 'Number toPrecision'
+
+    jsclass = 'Number'
+    own = {
+        'constructor': _constructor,
+        'toString': _to_string,
+        'toLocaleString': _to_locale_string,
+        'valueOf': _value_of,
+        'toFixed': _to_fixed,
+        'toExponential': _to_exponential,
+        'toPrecision': _to_precision
+    }
+
+
+class JSNumber(JSObject):
+    @staticmethod
+    def call(value=None):
+        return to_number(to_js(value)) if value is not None else 0
+
+    @staticmethod
+    def construct(value=None):
+        return JSNumberPrototype(to_number(to_js(value)) if value is not None else 0)
+
+    name = JSNumberPrototype.jsclass
+    own = {
+        'length': 1,
+        'prototype': JSNumberPrototype(),
+        'MAX_VALUE': 1.7976931348623157 * 10 ** 308,
+        'MIN_VALUE': 5 * 10 ** (-324),
+        'NAN': float('nan'),
+        'NEGATIVE_INFINITY': float('-inf'),
+        'POSITIVE_INFINITY': float('inf'),
+    }
diff --git a/youtube_dl/jsinterp2/jsbuilt_ins/jsobject.py b/youtube_dl/jsinterp2/jsbuilt_ins/jsobject.py
new file mode 100644
index 000000000..08f0f437f
--- /dev/null
+++ b/youtube_dl/jsinterp2/jsbuilt_ins/jsobject.py
@@ -0,0 +1,133 @@
+from __future__ import unicode_literals
+
+from .base import JSProtoBase, JSBase, null, undefined
+from .utils import to_js, js
+from .internals import to_object
+
+
+class JSObjectPrototype(JSProtoBase):
+
+    def __init__(self, value=None):
+        super(JSObjectPrototype, self).__init__()
+        if value is not None:
+            self.props.update(self.own)
+            self.own = self.value = value
+
+    @staticmethod
+    def _constructor(value=None):
+        return JSObject.construct(value)
+
+    def _to_string(self):
+        return 'object to string'
+
+    def _to_locale_string(self):
+        return 'object to locale string'
+
+    def _value_of(self):
+        return 'object value of'
+
+    def _has_own_property(self, v):
+        return v in self.own
+
+    def _is_prototype_of(self, v):
+        return 'object has own prop'
+
+    def _is_property_enumerable(self, v):
+        return 'object is property enumerable'
+
+    jsclass = 'Object'
+    own = {
+        'constructor': _constructor,
+        'toString': _to_string,
+        'toLocaleString': _to_locale_string,
+        'valueOf': _value_of,
+        'hasOwnProperty': _has_own_property,
+        'isPrototypeOf': _is_prototype_of,
+        'propertyIsEnumerable': _is_property_enumerable
+    }
+
+
+class JSObject(JSBase):
+
+    def __init__(self):
+        super(JSObject, self).__init__(self.name)
+
+    @staticmethod
+    def call(value=None):
+        if value is null or value is undefined or value is None:
+            return JSObject.construct(value)
+        return to_object(to_js(value))
+
+    @staticmethod
+    def construct(value=None):
+        from .jsboolean import JSBooleanPrototype
+        from .jsnumber import JSNumberPrototype
+        from .jsstring import JSStringPrototype
+
+        value = to_js(value)
+        # TODO set [[Prototype]], [[Class]], [[Extensible]], internal methods
+        if value is undefined or value is null:
+            return JSObjectPrototype({})
+        elif isinstance(value, JSObjectPrototype):
+            return value
+        elif isinstance(value, (JSStringPrototype, JSNumberPrototype, JSBooleanPrototype)):
+            return to_object(value)
+
+    def _get_prototype_of(self, o):
+        return 'object get prototype of'
+
+    def _get_own_property_descriptor(self, o, p):
+        return 'object desc'
+
+    @js
+    def _get_own_property_names(self, o):
+        return list(o.own.keys())
+
+    def _create(self, o, props=None):
+        return 'object create'
+
+    def _define_property(self, o, p, attr):
+        return 'object define prop'
+
+    def _define_properties(self, o, props):
+        return 'object define properties'
+
+    def _seal(self, o):
+        return 'object seal'
+
+    def _freeze(self, o):
+        return 'object freeze'
+
+    def _prevent_extensions(self, o):
+        return 'object prevent extension'
+
+    def _is_sealed(self, o):
+        return 'object is sealed'
+
+    def _is_frozen(self, o):
+        return 'object is frozen'
+
+    def _is_extensible(self, o):
+        return 'object is extensible'
+
+    def _keys(self, o):
+        return 'object keys'
+
+    name = JSObjectPrototype.jsclass
+    own = {
+        'length': 1,
+        'prototype': JSObjectPrototype(),
+        'getPrototypeOf': _get_prototype_of,
+        'getOwnPropertyDescriptor': _get_own_property_descriptor,
+        'getOwnPropertyNames': _get_own_property_names,
+        'create': _create,
+        'defineProperty': _define_property,
+        'defineProperties': _define_properties,
+        'seal': _seal,
+        'freeze': _freeze,
+        'preventExtensions': _prevent_extensions,
+        'isSealed': _is_sealed,
+        'isFrozen': _is_frozen,
+        'isExtensible': _is_extensible,
+        'keys': _keys
+    }
diff --git a/youtube_dl/jsinterp2/jsbuilt_ins/jsstring.py b/youtube_dl/jsinterp2/jsbuilt_ins/jsstring.py
new file mode 100644
index 000000000..bcabe74bd
--- /dev/null
+++ b/youtube_dl/jsinterp2/jsbuilt_ins/jsstring.py
@@ -0,0 +1,127 @@
+from __future__ import unicode_literals
+
+from .internals import to_string
+from .jsobject import JSObject, JSObjectPrototype
+
+
+class JSStringPrototype(JSObjectPrototype):
+
+    def __init__(self, value=None):
+        super(JSStringPrototype, self).__init__()
+        if value is None:
+            # prototype
+            value = ''
+        else:
+            self.value = value
+            self.own = {'length': self._length}
+
+    @property
+    def _length(self):
+        return len(self.value)
+
+    @staticmethod
+    def _constructor(value=None):
+        return JSString.construct(value)
+
+    def _to_string(self):
+        return self.value
+
+    def _value_of(self):
+        return self.value
+
+    def _char_at(self, pos):
+        return 'string char at'
+
+    def _char_code_at(self, pos):
+        return 'string char code at'
+
+    def _concat(self, *args):
+        return 'string concat'
+
+    def _index_of(self, search, pos):
+        return 'string index of'
+
+    def _last_index_of(self, search, pos):
+        return 'string last index of'
+
+    def _locale_compare(self, that):
+        return 'string locale compare'
+
+    def _match(self, regexp):
+        return 'string match'
+
+    def _replace(self, search, value):
+        return 'string replace'
+
+    def _search(self, regexp):
+        return 'string search'
+
+    def _slice(self, start, end):
+        return 'string slice'
+
+    def _split(self, sep):
+        return 'string split'
+
+    def _substring(self, start, end):
+        return 'string substring'
+
+    def _to_lower_case(self):
+        return 'string to lower case'
+
+    def _to_local_lower_case(self):
+        return 'string to local lower case'
+
+    def _to_upper_case(self):
+        return 'string to upper case'
+
+    def _to_local_upper_case(self):
+        return 'string to local upper case'
+
+    def _trim(self):
+        return 'string trim'
+
+    jsclass = 'String'
+    own = {
+        'length': _length,
+        'constructor': _constructor,
+        'toString': _to_string,
+        'valueOf': _value_of,
+        'charAt': _char_at,
+        'charCodeAt': _char_code_at,
+        'concat': _concat,
+        'indexOf': _index_of,
+        'lastIndexOf': _last_index_of,
+        'localeCompare': _locale_compare,
+        'match': _match,
+        'replace': _replace,
+        'search': _search,
+        'slice': _slice,
+        'split': _split,
+        'substring': _substring,
+        'toLowerCase': _to_lower_case,
+        'toLocalLowerCase': _to_local_lower_case,
+        'toUpperCase': _to_upper_case,
+        'toLocalUpperCase': _to_local_upper_case,
+        'trim': _trim
+    }
+
+
+class JSString(JSObject):
+
+    @staticmethod
+    def call(value=None):
+        return '' if value is None else to_string(value)
+
+    @staticmethod
+    def construct(value=None):
+        return JSStringPrototype('' if value is None else to_string(value))
+
+    def _from_char_code(self, *args):
+        return 'String from char code'
+
+    name = JSStringPrototype.jsclass
+    own = {
+        'length': 1,
+        'prototype': JSStringPrototype(),
+        'fromCharCode': _from_char_code
+    }
diff --git a/youtube_dl/jsinterp2/jsbuilt_ins/utils.py b/youtube_dl/jsinterp2/jsbuilt_ins/utils.py
new file mode 100644
index 000000000..65338cc1a
--- /dev/null
+++ b/youtube_dl/jsinterp2/jsbuilt_ins/utils.py
@@ -0,0 +1,45 @@
+from .base import (
+    JSProtoBase, native_bool, native_string, native_number, native_object, native_function, JSBase, native_array
+)
+
+
+def _get_formal_args(func):
+    return func.__code__.co_varnames[func.__code__.co_argcount - len((func.__defaults__))]
+
+
+def to_js(o, name=None):
+    from .base import undefined
+
+    from .jsarray import JSArrayPrototype
+    from .jsboolean import JSBooleanPrototype
+    from .jsfunction import JSFunctionPrototype
+    from .jsnumber import JSNumberPrototype
+    from .jsobject import JSObjectPrototype
+    from .jsstring import JSStringPrototype
+
+    if isinstance(o, JSProtoBase):
+        return o
+    elif o is None:
+        return undefined
+    elif isinstance(o, native_bool):
+        return JSBooleanPrototype(o)
+    elif isinstance(o, native_string):
+        return JSStringPrototype(o)
+    elif isinstance(o, native_number):
+        return JSNumberPrototype(o)
+    elif isinstance(o, native_object):
+        return JSObjectPrototype(o)
+    elif isinstance(o, native_function):
+        return JSFunctionPrototype(name, o, _get_formal_args(o))
+    elif isinstance(o, JSBase) and hasattr(o, 'call'):
+        return JSFunctionPrototype(o.name, o, _get_formal_args(o.call))
+    elif isinstance(o, native_array):
+        return JSArrayPrototype(o)
+    else:
+        raise Exception('Not allowed conversion %s to js' % type(o))
+
+
+def js(func):
+    def wrapper(*args, **kwargs):
+        return to_js(*func(*args, **kwargs))
+    return wrapper