--- a/js/src/jit-test/tests/basic/string-endswith.js
+++ b/js/src/jit-test/tests/basic/string-endswith.js
@@ -1,39 +1,262 @@
-assertEq("abc".endsWith("abc"), true);
-assertEq("abcd".endsWith("bcd"), true);
-assertEq("abc".endsWith("c"), true);
-assertEq("abc".endsWith("abcd"), false);
-assertEq("abc".endsWith("bbc"), false);
-assertEq("abc".endsWith("b"), false);
-assertEq("abc".endsWith("abc", 3), true);
-assertEq("abc".endsWith("bc", 3), true);
-assertEq("abc".endsWith("a", 3), false);
-assertEq("abc".endsWith("bc", 3), true);
-assertEq("abc".endsWith("a", 1), true);
-assertEq("abc".endsWith("abc", 1), false);
-assertEq("abc".endsWith("b", 2), true);
-assertEq("abc".endsWith("d", 2), false);
-assertEq("abc".endsWith("dcd", 2), false);
-assertEq("abc".endsWith("a", 42), false);
-assertEq("abc".endsWith("bc", Infinity), true);
-assertEq("abc".endsWith("a", Infinity), false);
-assertEq("abc".endsWith("bc", undefined), true);
-assertEq("abc".endsWith("bc", -43), false);
-assertEq("abc".endsWith("bc", -Infinity), false);
-assertEq("abc".endsWith("bc", NaN), false);
-var myobj = {toString : (function () "abc"), endsWith : String.prototype.endsWith};
-assertEq(myobj.endsWith("abc"), true);
-assertEq(myobj.endsWith("ab"), false);
-var gotStr = false, gotPos = false;
-myobj = {toString : (function () {
-    assertEq(gotPos, false);
-    gotStr = true;
-    return "xyz";
-}),
-endsWith : String.prototype.endsWith};
-var idx = {valueOf : (function () {
-    assertEq(gotStr, true);
-    gotPos = true;
-    return 42;
-})};
-myobj.endsWith("elephant", idx);
-assertEq(gotPos, true);
+/*
+* Copyright (c) 2013 Mathias Bynens. All rights reserved.
+*
+* Permission is hereby granted, free of charge, to any person obtaining a
+* copy of this software and associated documentation files (the "Software"),
+* to deal in the Software without restriction, including without limitation
+* the rights to use, copy, modify, merge, publish, distribute, sublicense,
+* and/or sell copies of the Software, and to permit persons to whom the
+* Software is furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in
+* all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+* DEALINGS IN THE SOFTWARE.
+*/
+
+function assertThrows(fun, errorType) {
+  try {
+    fun();
+    assertEq(true, false, "Expected error, but none was thrown");
+  } catch (e) {
+    assertEq(e instanceof errorType, true, "Wrong error type thrown");
+  }
+}
+assertEq(String.prototype.endsWith.length, 1);
+assertEq(String.prototype.propertyIsEnumerable('endsWith'), false);
+
+assertEq('undefined'.endsWith(), true);
+assertEq('undefined'.endsWith(undefined), true);
+assertEq('undefined'.endsWith(null), false);
+assertEq('null'.endsWith(), false);
+assertEq('null'.endsWith(undefined), false);
+assertEq('null'.endsWith(null), true);
+
+assertEq('abc'.endsWith(), false);
+assertEq('abc'.endsWith(''), true);
+assertEq('abc'.endsWith('\0'), false);
+assertEq('abc'.endsWith('c'), true);
+assertEq('abc'.endsWith('b'), false);
+assertEq('abc'.endsWith('a'), false);
+assertEq('abc'.endsWith('ab'), false);
+assertEq('abc'.endsWith('bc'), true);
+assertEq('abc'.endsWith('abc'), true);
+assertEq('abc'.endsWith('bcd'), false);
+assertEq('abc'.endsWith('abcd'), false);
+assertEq('abc'.endsWith('bcde'), false);
+
+assertEq('abc'.endsWith('', NaN), true);
+assertEq('abc'.endsWith('\0', NaN), false);
+assertEq('abc'.endsWith('c', NaN), false);
+assertEq('abc'.endsWith('b', NaN), false);
+assertEq('abc'.endsWith('a', NaN), false);
+assertEq('abc'.endsWith('ab', NaN), false);
+assertEq('abc'.endsWith('bc', NaN), false);
+assertEq('abc'.endsWith('abc', NaN), false);
+assertEq('abc'.endsWith('bcd', NaN), false);
+assertEq('abc'.endsWith('abcd', NaN), false);
+assertEq('abc'.endsWith('bcde', NaN), false);
+
+assertEq('abc'.endsWith('', false), true);
+assertEq('abc'.endsWith('\0', false), false);
+assertEq('abc'.endsWith('c', false), false);
+assertEq('abc'.endsWith('b', false), false);
+assertEq('abc'.endsWith('a', false), false);
+assertEq('abc'.endsWith('ab', false), false);
+assertEq('abc'.endsWith('bc', false), false);
+assertEq('abc'.endsWith('abc', false), false);
+assertEq('abc'.endsWith('bcd', false), false);
+assertEq('abc'.endsWith('abcd', false), false);
+assertEq('abc'.endsWith('bcde', false), false);
+
+assertEq('abc'.endsWith('', undefined), true);
+assertEq('abc'.endsWith('\0', undefined), false);
+assertEq('abc'.endsWith('c', undefined), true);
+assertEq('abc'.endsWith('b', undefined), false);
+assertEq('abc'.endsWith('a', undefined), false);
+assertEq('abc'.endsWith('ab', undefined), false);
+assertEq('abc'.endsWith('bc', undefined), true);
+assertEq('abc'.endsWith('abc', undefined), true);
+assertEq('abc'.endsWith('bcd', undefined), false);
+assertEq('abc'.endsWith('abcd', undefined), false);
+assertEq('abc'.endsWith('bcde', undefined), false);
+
+assertEq('abc'.endsWith('', null), true);
+assertEq('abc'.endsWith('\0', null), false);
+assertEq('abc'.endsWith('c', null), false);
+assertEq('abc'.endsWith('b', null), false);
+assertEq('abc'.endsWith('a', null), false);
+assertEq('abc'.endsWith('ab', null), false);
+assertEq('abc'.endsWith('bc', null), false);
+assertEq('abc'.endsWith('abc', null), false);
+assertEq('abc'.endsWith('bcd', null), false);
+assertEq('abc'.endsWith('abcd', null), false);
+assertEq('abc'.endsWith('bcde', null), false);
+
+assertEq('abc'.endsWith('', -Infinity), true);
+assertEq('abc'.endsWith('\0', -Infinity), false);
+assertEq('abc'.endsWith('c', -Infinity), false);
+assertEq('abc'.endsWith('b', -Infinity), false);
+assertEq('abc'.endsWith('a', -Infinity), false);
+assertEq('abc'.endsWith('ab', -Infinity), false);
+assertEq('abc'.endsWith('bc', -Infinity), false);
+assertEq('abc'.endsWith('abc', -Infinity), false);
+assertEq('abc'.endsWith('bcd', -Infinity), false);
+assertEq('abc'.endsWith('abcd', -Infinity), false);
+assertEq('abc'.endsWith('bcde', -Infinity), false);
+
+assertEq('abc'.endsWith('', -1), true);
+assertEq('abc'.endsWith('\0', -1), false);
+assertEq('abc'.endsWith('c', -1), false);
+assertEq('abc'.endsWith('b', -1), false);
+assertEq('abc'.endsWith('a', -1), false);
+assertEq('abc'.endsWith('ab', -1), false);
+assertEq('abc'.endsWith('bc', -1), false);
+assertEq('abc'.endsWith('abc', -1), false);
+assertEq('abc'.endsWith('bcd', -1), false);
+assertEq('abc'.endsWith('abcd', -1), false);
+assertEq('abc'.endsWith('bcde', -1), false);
+
+assertEq('abc'.endsWith('', -0), true);
+assertEq('abc'.endsWith('\0', -0), false);
+assertEq('abc'.endsWith('c', -0), false);
+assertEq('abc'.endsWith('b', -0), false);
+assertEq('abc'.endsWith('a', -0), false);
+assertEq('abc'.endsWith('ab', -0), false);
+assertEq('abc'.endsWith('bc', -0), false);
+assertEq('abc'.endsWith('abc', -0), false);
+assertEq('abc'.endsWith('bcd', -0), false);
+assertEq('abc'.endsWith('abcd', -0), false);
+assertEq('abc'.endsWith('bcde', -0), false);
+
+assertEq('abc'.endsWith('', +0), true);
+assertEq('abc'.endsWith('\0', +0), false);
+assertEq('abc'.endsWith('c', +0), false);
+assertEq('abc'.endsWith('b', +0), false);
+assertEq('abc'.endsWith('a', +0), false);
+assertEq('abc'.endsWith('ab', +0), false);
+assertEq('abc'.endsWith('bc', +0), false);
+assertEq('abc'.endsWith('abc', +0), false);
+assertEq('abc'.endsWith('bcd', +0), false);
+assertEq('abc'.endsWith('abcd', +0), false);
+assertEq('abc'.endsWith('bcde', +0), false);
+
+assertEq('abc'.endsWith('', 1), true);
+assertEq('abc'.endsWith('\0', 1), false);
+assertEq('abc'.endsWith('c', 1), false);
+assertEq('abc'.endsWith('b', 1), false);
+assertEq('abc'.endsWith('ab', 1), false);
+assertEq('abc'.endsWith('bc', 1), false);
+assertEq('abc'.endsWith('abc', 1), false);
+assertEq('abc'.endsWith('bcd', 1), false);
+assertEq('abc'.endsWith('abcd', 1), false);
+assertEq('abc'.endsWith('bcde', 1), false);
+
+assertEq('abc'.endsWith('', 2), true);
+assertEq('abc'.endsWith('\0', 2), false);
+assertEq('abc'.endsWith('c', 2), false);
+assertEq('abc'.endsWith('b', 2), true);
+assertEq('abc'.endsWith('ab', 2), true);
+assertEq('abc'.endsWith('bc', 2), false);
+assertEq('abc'.endsWith('abc', 2), false);
+assertEq('abc'.endsWith('bcd', 2), false);
+assertEq('abc'.endsWith('abcd', 2), false);
+assertEq('abc'.endsWith('bcde', 2), false);
+
+assertEq('abc'.endsWith('', +Infinity), true);
+assertEq('abc'.endsWith('\0', +Infinity), false);
+assertEq('abc'.endsWith('c', +Infinity), true);
+assertEq('abc'.endsWith('b', +Infinity), false);
+assertEq('abc'.endsWith('a', +Infinity), false);
+assertEq('abc'.endsWith('ab', +Infinity), false);
+assertEq('abc'.endsWith('bc', +Infinity), true);
+assertEq('abc'.endsWith('abc', +Infinity), true);
+assertEq('abc'.endsWith('bcd', +Infinity), false);
+assertEq('abc'.endsWith('abcd', +Infinity), false);
+assertEq('abc'.endsWith('bcde', +Infinity), false);
+
+assertEq('abc'.endsWith('', true), true);
+assertEq('abc'.endsWith('\0', true), false);
+assertEq('abc'.endsWith('c', true), false);
+assertEq('abc'.endsWith('b', true), false);
+assertEq('abc'.endsWith('ab', true), false);
+assertEq('abc'.endsWith('bc', true), false);
+assertEq('abc'.endsWith('abc', true), false);
+assertEq('abc'.endsWith('bcd', true), false);
+assertEq('abc'.endsWith('abcd', true), false);
+assertEq('abc'.endsWith('bcde', true), false);
+
+assertEq('abc'.endsWith('', 'x'), true);
+assertEq('abc'.endsWith('\0', 'x'), false);
+assertEq('abc'.endsWith('c', 'x'), false);
+assertEq('abc'.endsWith('b', 'x'), false);
+assertEq('abc'.endsWith('a', 'x'), false);
+assertEq('abc'.endsWith('ab', 'x'), false);
+assertEq('abc'.endsWith('bc', 'x'), false);
+assertEq('abc'.endsWith('abc', 'x'), false);
+assertEq('abc'.endsWith('bcd', 'x'), false);
+assertEq('abc'.endsWith('abcd', 'x'), false);
+assertEq('abc'.endsWith('bcde', 'x'), false);
+
+assertEq('[a-z]+(bar)?'.endsWith('(bar)?'), true);
+assertThrows(function() { '[a-z]+(bar)?'.endsWith(/(bar)?/); }, TypeError);
+assertEq('[a-z]+(bar)?'.endsWith('[a-z]+', 6), true);
+assertThrows(function() { '[a-z]+(bar)?'.endsWith(/(bar)?/); }, TypeError);
+assertThrows(function() { '[a-z]+/(bar)?/'.endsWith(/(bar)?/); }, TypeError);
+var global = newGlobal();
+global.eval('this.re = /(bar)?/');
+assertThrows(function() { '[a-z]+/(bar)?/'.endsWith(global.re); }, TypeError);
+
+// http://mathiasbynens.be/notes/javascript-unicode#poo-test
+var string = 'I\xF1t\xEBrn\xE2ti\xF4n\xE0liz\xE6ti\xF8n\u2603\uD83D\uDCA9';
+assertEq(string.endsWith(''), true);
+assertEq(string.endsWith('\xF1t\xEBr'), false);
+assertEq(string.endsWith('\xF1t\xEBr', 5), true);
+assertEq(string.endsWith('\xE0liz\xE6'), false);
+assertEq(string.endsWith('\xE0liz\xE6', 16), true);
+assertEq(string.endsWith('\xF8n\u2603\uD83D\uDCA9'), true);
+assertEq(string.endsWith('\xF8n\u2603\uD83D\uDCA9', 23), true);
+assertEq(string.endsWith('\u2603'), false);
+assertEq(string.endsWith('\u2603', 21), true);
+assertEq(string.endsWith('\uD83D\uDCA9'), true);
+assertEq(string.endsWith('\uD83D\uDCA9', 23), true);
+
+assertThrows(function() { String.prototype.endsWith.call(undefined); }, TypeError);
+assertThrows(function() { String.prototype.endsWith.call(undefined, 'b'); }, TypeError);
+assertThrows(function() { String.prototype.endsWith.call(undefined, 'b', 4); }, TypeError);
+assertThrows(function() { String.prototype.endsWith.call(null); }, TypeError);
+assertThrows(function() { String.prototype.endsWith.call(null, 'b'); }, TypeError);
+assertThrows(function() { String.prototype.endsWith.call(null, 'b', 4); }, TypeError);
+assertEq(String.prototype.endsWith.call(42, '2'), true);
+assertEq(String.prototype.endsWith.call(42, '4'), false);
+assertEq(String.prototype.endsWith.call(42, 'b', 4), false);
+assertEq(String.prototype.endsWith.call(42, '2', 1), false);
+assertEq(String.prototype.endsWith.call(42, '2', 4), true);
+assertEq(String.prototype.endsWith.call({ 'toString': function() { return 'abc'; } }, 'b', 0), false);
+assertEq(String.prototype.endsWith.call({ 'toString': function() { return 'abc'; } }, 'b', 1), false);
+assertEq(String.prototype.endsWith.call({ 'toString': function() { return 'abc'; } }, 'b', 2), true);
+assertThrows(function() { String.prototype.endsWith.call({ 'toString': function() { throw RangeError(); } }, /./); }, RangeError);
+assertThrows(function() { String.prototype.endsWith.call({ 'toString': function() { return 'abc' } }, /./); }, TypeError);
+
+assertThrows(function() { String.prototype.endsWith.apply(undefined); }, TypeError);
+assertThrows(function() { String.prototype.endsWith.apply(undefined, ['b']); }, TypeError);
+assertThrows(function() { String.prototype.endsWith.apply(undefined, ['b', 4]); }, TypeError);
+assertThrows(function() { String.prototype.endsWith.apply(null); }, TypeError);
+assertThrows(function() { String.prototype.endsWith.apply(null, ['b']); }, TypeError);
+assertThrows(function() { String.prototype.endsWith.apply(null, ['b', 4]); }, TypeError);
+assertEq(String.prototype.endsWith.apply(42, ['2']), true);
+assertEq(String.prototype.endsWith.apply(42, ['4']), false);
+assertEq(String.prototype.endsWith.apply(42, ['b', 4]), false);
+assertEq(String.prototype.endsWith.apply(42, ['2', 1]), false);
+assertEq(String.prototype.endsWith.apply(42, ['2', 4]), true);
+assertEq(String.prototype.endsWith.apply({ 'toString': function() { return 'abc'; } }, ['b', 0]), false);
+assertEq(String.prototype.endsWith.apply({ 'toString': function() { return 'abc'; } }, ['b', 1]), false);
+assertEq(String.prototype.endsWith.apply({ 'toString': function() { return 'abc'; } }, ['b', 2]), true);
+assertThrows(function() { String.prototype.endsWith.apply({ 'toString': function() { throw RangeError(); } }, [/./]); }, RangeError);
+assertThrows(function() { String.prototype.endsWith.apply({ 'toString': function() { return 'abc' } }, [/./]); }, TypeError);

--- a/js/src/jit-test/tests/basic/string-startswith.js
+++ b/js/src/jit-test/tests/basic/string-startswith.js
@@ -1,39 +1,243 @@
-assertEq("abc".startsWith("abc"), true);
-assertEq("abcd".startsWith("abc"), true);
-assertEq("abc".startsWith("a"), true);
-assertEq("abc".startsWith("abcd"), false);
-assertEq("abc".startsWith("bcde"), false);
-assertEq("abc".startsWith("b"), false);
-assertEq("abc".startsWith("abc", 0), true);
-assertEq("abc".startsWith("bc", 0), false);
-assertEq("abc".startsWith("bc", 1), true);
-assertEq("abc".startsWith("c", 1), false);
-assertEq("abc".startsWith("abc", 1), false);
-assertEq("abc".startsWith("c", 2), true);
-assertEq("abc".startsWith("d", 2), false);
-assertEq("abc".startsWith("dcd", 2), false);
-assertEq("abc".startsWith("a", 42), false);
-assertEq("abc".startsWith("a", Infinity), false);
-assertEq("abc".startsWith("a", NaN), true);
-assertEq("abc".startsWith("b", NaN), false);
-assertEq("abc".startsWith("ab", -43), true);
-assertEq("abc".startsWith("ab", -Infinity), true);
-assertEq("abc".startsWith("bc", -42), false);
-assertEq("abc".startsWith("bc", -Infinity), false);
-var myobj = {toString : (function () "abc"), startsWith : String.prototype.startsWith};
-assertEq(myobj.startsWith("abc"), true);
-assertEq(myobj.startsWith("bc"), false);
-var gotStr = false, gotPos = false;
-myobj = {toString : (function () {
-    assertEq(gotPos, false);
-    gotStr = true;
-    return "xyz";
-}),
-startsWith : String.prototype.startsWith};
-var idx = {valueOf : (function () {
-    assertEq(gotStr, true);
-    gotPos = true;
-    return 42;
-})};
-myobj.startsWith("elephant", idx);
-assertEq(gotPos, true);
+/*
+* Copyright (c) 2013 Mathias Bynens. All rights reserved.
+*
+* Permission is hereby granted, free of charge, to any person obtaining a
+* copy of this software and associated documentation files (the "Software"),
+* to deal in the Software without restriction, including without limitation
+* the rights to use, copy, modify, merge, publish, distribute, sublicense,
+* and/or sell copies of the Software, and to permit persons to whom the
+* Software is furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in
+* all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+* DEALINGS IN THE SOFTWARE.
+*/
+
+function assertThrows(fun, errorType) {
+  try {
+    fun();
+    assertEq(true, false, "Expected error, but none was thrown");
+  } catch (e) {
+    assertEq(e instanceof errorType, true, "Wrong error type thrown");
+  }
+}
+
+Object.prototype[1] = 2; // try to break `arguments[1]`
+
+assertEq(String.prototype.startsWith.length, 1);
+assertEq(String.prototype.propertyIsEnumerable('startsWith'), false);
+
+assertEq('undefined'.startsWith(), true);
+assertEq('undefined'.startsWith(undefined), true);
+assertEq('undefined'.startsWith(null), false);
+assertEq('null'.startsWith(), false);
+assertEq('null'.startsWith(undefined), false);
+assertEq('null'.startsWith(null), true);
+
+assertEq('abc'.startsWith(), false);
+assertEq('abc'.startsWith(''), true);
+assertEq('abc'.startsWith('\0'), false);
+assertEq('abc'.startsWith('a'), true);
+assertEq('abc'.startsWith('b'), false);
+assertEq('abc'.startsWith('ab'), true);
+assertEq('abc'.startsWith('bc'), false);
+assertEq('abc'.startsWith('abc'), true);
+assertEq('abc'.startsWith('bcd'), false);
+assertEq('abc'.startsWith('abcd'), false);
+assertEq('abc'.startsWith('bcde'), false);
+
+assertEq('abc'.startsWith('', NaN), true);
+assertEq('abc'.startsWith('\0', NaN), false);
+assertEq('abc'.startsWith('a', NaN), true);
+assertEq('abc'.startsWith('b', NaN), false);
+assertEq('abc'.startsWith('ab', NaN), true);
+assertEq('abc'.startsWith('bc', NaN), false);
+assertEq('abc'.startsWith('abc', NaN), true);
+assertEq('abc'.startsWith('bcd', NaN), false);
+assertEq('abc'.startsWith('abcd', NaN), false);
+assertEq('abc'.startsWith('bcde', NaN), false);
+
+assertEq('abc'.startsWith('', false), true);
+assertEq('abc'.startsWith('\0', false), false);
+assertEq('abc'.startsWith('a', false), true);
+assertEq('abc'.startsWith('b', false), false);
+assertEq('abc'.startsWith('ab', false), true);
+assertEq('abc'.startsWith('bc', false), false);
+assertEq('abc'.startsWith('abc', false), true);
+assertEq('abc'.startsWith('bcd', false), false);
+assertEq('abc'.startsWith('abcd', false), false);
+assertEq('abc'.startsWith('bcde', false), false);
+
+assertEq('abc'.startsWith('', undefined), true);
+assertEq('abc'.startsWith('\0', undefined), false);
+assertEq('abc'.startsWith('a', undefined), true);
+assertEq('abc'.startsWith('b', undefined), false);
+assertEq('abc'.startsWith('ab', undefined), true);
+assertEq('abc'.startsWith('bc', undefined), false);
+assertEq('abc'.startsWith('abc', undefined), true);
+assertEq('abc'.startsWith('bcd', undefined), false);
+assertEq('abc'.startsWith('abcd', undefined), false);
+assertEq('abc'.startsWith('bcde', undefined), false);
+
+assertEq('abc'.startsWith('', null), true);
+assertEq('abc'.startsWith('\0', null), false);
+assertEq('abc'.startsWith('a', null), true);
+assertEq('abc'.startsWith('b', null), false);
+assertEq('abc'.startsWith('ab', null), true);
+assertEq('abc'.startsWith('bc', null), false);
+assertEq('abc'.startsWith('abc', null), true);
+assertEq('abc'.startsWith('bcd', null), false);
+assertEq('abc'.startsWith('abcd', null), false);
+assertEq('abc'.startsWith('bcde', null), false);
+
+assertEq('abc'.startsWith('', -Infinity), true);
+assertEq('abc'.startsWith('\0', -Infinity), false);
+assertEq('abc'.startsWith('a', -Infinity), true);
+assertEq('abc'.startsWith('b', -Infinity), false);
+assertEq('abc'.startsWith('ab', -Infinity), true);
+assertEq('abc'.startsWith('bc', -Infinity), false);
+assertEq('abc'.startsWith('abc', -Infinity), true);
+assertEq('abc'.startsWith('bcd', -Infinity), false);
+assertEq('abc'.startsWith('abcd', -Infinity), false);
+assertEq('abc'.startsWith('bcde', -Infinity), false);
+
+assertEq('abc'.startsWith('', -1), true);
+assertEq('abc'.startsWith('\0', -1), false);
+assertEq('abc'.startsWith('a', -1), true);
+assertEq('abc'.startsWith('b', -1), false);
+assertEq('abc'.startsWith('ab', -1), true);
+assertEq('abc'.startsWith('bc', -1), false);
+assertEq('abc'.startsWith('abc', -1), true);
+assertEq('abc'.startsWith('bcd', -1), false);
+assertEq('abc'.startsWith('abcd', -1), false);
+assertEq('abc'.startsWith('bcde', -1), false);
+
+assertEq('abc'.startsWith('', -0), true);
+assertEq('abc'.startsWith('\0', -0), false);
+assertEq('abc'.startsWith('a', -0), true);
+assertEq('abc'.startsWith('b', -0), false);
+assertEq('abc'.startsWith('ab', -0), true);
+assertEq('abc'.startsWith('bc', -0), false);
+assertEq('abc'.startsWith('abc', -0), true);
+assertEq('abc'.startsWith('bcd', -0), false);
+assertEq('abc'.startsWith('abcd', -0), false);
+assertEq('abc'.startsWith('bcde', -0), false);
+
+assertEq('abc'.startsWith('', +0), true);
+assertEq('abc'.startsWith('\0', +0), false);
+assertEq('abc'.startsWith('a', +0), true);
+assertEq('abc'.startsWith('b', +0), false);
+assertEq('abc'.startsWith('ab', +0), true);
+assertEq('abc'.startsWith('bc', +0), false);
+assertEq('abc'.startsWith('abc', +0), true);
+assertEq('abc'.startsWith('bcd', +0), false);
+assertEq('abc'.startsWith('abcd', +0), false);
+assertEq('abc'.startsWith('bcde', +0), false);
+
+assertEq('abc'.startsWith('', 1), true);
+assertEq('abc'.startsWith('\0', 1), false);
+assertEq('abc'.startsWith('a', 1), false);
+assertEq('abc'.startsWith('b', 1), true);
+assertEq('abc'.startsWith('ab', 1), false);
+assertEq('abc'.startsWith('bc', 1), true);
+assertEq('abc'.startsWith('abc', 1), false);
+assertEq('abc'.startsWith('bcd', 1), false);
+assertEq('abc'.startsWith('abcd', 1), false);
+assertEq('abc'.startsWith('bcde', 1), false);
+
+assertEq('abc'.startsWith('', +Infinity), true);
+assertEq('abc'.startsWith('\0', +Infinity), false);
+assertEq('abc'.startsWith('a', +Infinity), false);
+assertEq('abc'.startsWith('b', +Infinity), false);
+assertEq('abc'.startsWith('ab', +Infinity), false);
+assertEq('abc'.startsWith('bc', +Infinity), false);
+assertEq('abc'.startsWith('abc', +Infinity), false);
+assertEq('abc'.startsWith('bcd', +Infinity), false);
+assertEq('abc'.startsWith('abcd', +Infinity), false);
+assertEq('abc'.startsWith('bcde', +Infinity), false);
+
+assertEq('abc'.startsWith('', true), true);
+assertEq('abc'.startsWith('\0', true), false);
+assertEq('abc'.startsWith('a', true), false);
+assertEq('abc'.startsWith('b', true), true);
+assertEq('abc'.startsWith('ab', true), false);
+assertEq('abc'.startsWith('bc', true), true);
+assertEq('abc'.startsWith('abc', true), false);
+assertEq('abc'.startsWith('bcd', true), false);
+assertEq('abc'.startsWith('abcd', true), false);
+assertEq('abc'.startsWith('bcde', true), false);
+
+assertEq('abc'.startsWith('', 'x'), true);
+assertEq('abc'.startsWith('\0', 'x'), false);
+assertEq('abc'.startsWith('a', 'x'), true);
+assertEq('abc'.startsWith('b', 'x'), false);
+assertEq('abc'.startsWith('ab', 'x'), true);
+assertEq('abc'.startsWith('bc', 'x'), false);
+assertEq('abc'.startsWith('abc', 'x'), true);
+assertEq('abc'.startsWith('bcd', 'x'), false);
+assertEq('abc'.startsWith('abcd', 'x'), false);
+assertEq('abc'.startsWith('bcde', 'x'), false);
+
+assertEq('[a-z]+(bar)?'.startsWith('[a-z]+'), true);
+assertThrows(function() { '[a-z]+(bar)?'.startsWith(/[a-z]+/); }, TypeError);
+assertEq('[a-z]+(bar)?'.startsWith('(bar)?', 6), true);
+assertThrows(function() { '[a-z]+(bar)?'.startsWith(/(bar)?/); }, TypeError);
+assertThrows(function() { '[a-z]+/(bar)?/'.startsWith(/(bar)?/); }, TypeError);
+var global = newGlobal();
+global.eval('this.re = /(bar)?/');
+assertThrows(function() { '[a-z]+/(bar)?/'.startsWith(global.re); }, TypeError);
+
+// http://mathiasbynens.be/notes/javascript-unicode#poo-test
+var string = 'I\xF1t\xEBrn\xE2ti\xF4n\xE0liz\xE6ti\xF8n\u2603\uD83D\uDCA9';
+assertEq(string.startsWith(''), true);
+assertEq(string.startsWith('\xF1t\xEBr'), false);
+assertEq(string.startsWith('\xF1t\xEBr', 1), true);
+assertEq(string.startsWith('\xE0liz\xE6'), false);
+assertEq(string.startsWith('\xE0liz\xE6', 11), true);
+assertEq(string.startsWith('\xF8n\u2603\uD83D\uDCA9'), false);
+assertEq(string.startsWith('\xF8n\u2603\uD83D\uDCA9', 18), true);
+assertEq(string.startsWith('\u2603'), false);
+assertEq(string.startsWith('\u2603', 20), true);
+assertEq(string.startsWith('\uD83D\uDCA9'), false);
+assertEq(string.startsWith('\uD83D\uDCA9', 21), true);
+
+assertThrows(function() { String.prototype.startsWith.call(undefined); }, TypeError);
+assertThrows(function() { String.prototype.startsWith.call(undefined, 'b'); }, TypeError);
+assertThrows(function() { String.prototype.startsWith.call(undefined, 'b', 4); }, TypeError);
+assertThrows(function() { String.prototype.startsWith.call(null); }, TypeError);
+assertThrows(function() { String.prototype.startsWith.call(null, 'b'); }, TypeError);
+assertThrows(function() { String.prototype.startsWith.call(null, 'b', 4); }, TypeError);
+assertEq(String.prototype.startsWith.call(42, '2'), false);
+assertEq(String.prototype.startsWith.call(42, '4'), true);
+assertEq(String.prototype.startsWith.call(42, 'b', 4), false);
+assertEq(String.prototype.startsWith.call(42, '2', 1), true);
+assertEq(String.prototype.startsWith.call(42, '2', 4), false);
+assertEq(String.prototype.startsWith.call({ 'toString': function() { return 'abc'; } }, 'b', 0), false);
+assertEq(String.prototype.startsWith.call({ 'toString': function() { return 'abc'; } }, 'b', 1), true);
+assertEq(String.prototype.startsWith.call({ 'toString': function() { return 'abc'; } }, 'b', 2), false);
+assertThrows(function() { String.prototype.startsWith.call({ 'toString': function() { throw RangeError(); } }, /./); }, RangeError);
+assertThrows(function() { String.prototype.startsWith.call({ 'toString': function() { return 'abc'; } }, /./); }, TypeError);
+
+assertThrows(function() { String.prototype.startsWith.apply(undefined); }, TypeError);
+assertThrows(function() { String.prototype.startsWith.apply(undefined, ['b']); }, TypeError);
+assertThrows(function() { String.prototype.startsWith.apply(undefined, ['b', 4]); }, TypeError);
+assertThrows(function() { String.prototype.startsWith.apply(null); }, TypeError);
+assertThrows(function() { String.prototype.startsWith.apply(null, ['b']); }, TypeError);
+assertThrows(function() { String.prototype.startsWith.apply(null, ['b', 4]); }, TypeError);
+assertEq(String.prototype.startsWith.apply(42, ['2']), false);
+assertEq(String.prototype.startsWith.apply(42, ['4']), true);
+assertEq(String.prototype.startsWith.apply(42, ['b', 4]), false);
+assertEq(String.prototype.startsWith.apply(42, ['2', 1]), true);
+assertEq(String.prototype.startsWith.apply(42, ['2', 4]), false);
+assertEq(String.prototype.startsWith.apply({ 'toString': function() { return 'abc'; } }, ['b', 0]), false);
+assertEq(String.prototype.startsWith.apply({ 'toString': function() { return 'abc'; } }, ['b', 1]), true);
+assertEq(String.prototype.startsWith.apply({ 'toString': function() { return 'abc'; } }, ['b', 2]), false);
+assertThrows(function() { String.prototype.startsWith.apply({ 'toString': function() { throw RangeError(); } }, [/./]); }, RangeError);
+assertThrows(function() { String.prototype.startsWith.apply({ 'toString': function() { return 'abc'; } }, [/./]); }, TypeError);

--- a/js/src/js.msg
+++ b/js/src/js.msg
@@ -429,8 +429,9 @@ MSG_DEF(JSMSG_MODULE_SPEC_AFTER_FROM,   
 MSG_DEF(JSMSG_MODULES_NOT_IMPLEMENTED,  375, 0, JSEXN_SYNTAXERR, "modules are not implemented yet")
 MSG_DEF(JSMSG_EXPORT_DECL_AT_TOP_LEVEL, 376, 0, JSEXN_SYNTAXERR, "export declarations may only appear at top level")
 MSG_DEF(JSMSG_RC_AFTER_EXPORT_SPEC_LIST, 377, 0, JSEXN_SYNTAXERR, "missing '}' after export specifier list")
 MSG_DEF(JSMSG_NO_EXPORT_NAME,           378, 0, JSEXN_SYNTAXERR, "missing export name")
 MSG_DEF(JSMSG_DECLARATION_AFTER_EXPORT, 379, 0, JSEXN_SYNTAXERR, "missing declaration after 'export' keyword")
 MSG_DEF(JSMSG_INVALID_PROTOTYPE,        380, 0, JSEXN_TYPEERR, "prototype field is not an object")
 MSG_DEF(JSMSG_TYPEDOBJECT_HANDLE_TO_UNSIZED, 381, 0, JSEXN_TYPEERR, "cannot create a handle to an unsized type")
 MSG_DEF(JSMSG_SETPROTOTYPEOF_FAIL,      382, 0, JSEXN_TYPEERR, "[[SetPrototypeOf]] failed")
+MSG_DEF(JSMSG_INVALID_ARG_TYPE,         383, 3, JSEXN_TYPEERR, "Invalid type: {0} can't be a{1} {2}")

--- a/js/src/jsstr.cpp
+++ b/js/src/jsstr.cpp
@@ -1417,125 +1417,137 @@ str_lastIndexOf(JSContext *cx, unsigned 
         }
       break_continue:;
     }
 
     args.rval().setInt32(-1);
     return true;
 }
 
-/* ES6 20120927 draft 15.5.4.22. */
+/* ES6 20131108 draft 21.1.3.18. */
 static bool
 str_startsWith(JSContext *cx, unsigned argc, Value *vp)
 {
     CallArgs args = CallArgsFromVp(argc, vp);
 
     // Steps 1, 2, and 3
     RootedString str(cx, ThisToStringForStringProto(cx, args));
     if (!str)
         return false;
 
-    // Steps 4 and 5
+    // Step 4
+    if (args.get(0).isObject() && IsObjectWithClass(args[0], ESClass_RegExp, cx)) {
+        JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_INVALID_ARG_TYPE,
+                             "first", "", "Regular Expression");
+        return false;
+    }
+
+    // Steps 5 and 6
     Rooted<JSLinearString*> searchStr(cx, ArgToRootedString(cx, args, 0));
     if (!searchStr)
         return false;
 
-    // Steps 6 and 7
+    // Steps 7 and 8
     uint32_t pos = 0;
     if (args.hasDefined(1)) {
         if (args[1].isInt32()) {
             int i = args[1].toInt32();
             pos = (i < 0) ? 0U : uint32_t(i);
         } else {
             double d;
             if (!ToInteger(cx, args[1], &d))
                 return false;
             pos = uint32_t(Min(Max(d, 0.0), double(UINT32_MAX)));
         }
     }
 
-    // Step 8
+    // Step 9
     uint32_t textLen = str->length();
     const jschar *textChars = str->getChars(cx);
     if (!textChars)
         return false;
 
-    // Step 9
+    // Step 10
     uint32_t start = Min(Max(pos, 0U), textLen);
 
-    // Step 10
+    // Step 11
     uint32_t searchLen = searchStr->length();
     const jschar *searchChars = searchStr->chars();
 
-    // Step 11
+    // Step 12
     if (searchLen + start < searchLen || searchLen + start > textLen) {
         args.rval().setBoolean(false);
         return true;
     }
 
-    // Steps 12 and 13
+    // Steps 13 and 14
     args.rval().setBoolean(PodEqual(textChars + start, searchChars, searchLen));
     return true;
 }
 
-/* ES6 20120708 draft 15.5.4.23. */
+/* ES6 20131108 draft 21.1.3.7. */
 static bool
 str_endsWith(JSContext *cx, unsigned argc, Value *vp)
 {
     CallArgs args = CallArgsFromVp(argc, vp);
 
     // Steps 1, 2, and 3
     RootedString str(cx, ThisToStringForStringProto(cx, args));
     if (!str)
         return false;
 
-    // Steps 4 and 5
+    // Step 4
+    if (args.get(0).isObject() && IsObjectWithClass(args[0], ESClass_RegExp, cx)) {
+        JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_INVALID_ARG_TYPE,
+                             "first", "", "Regular Expression");
+        return false;
+    }
+
+    // Steps 5 and 6
     Rooted<JSLinearString *> searchStr(cx, ArgToRootedString(cx, args, 0));
     if (!searchStr)
         return false;
 
-    // Step 6
+    // Step 7
     uint32_t textLen = str->length();
-
-    // Steps 7 and 8
+    const jschar *textChars = str->getChars(cx);
+    if (!textChars)
+        return false;
+
+    // Steps 8 and 9
     uint32_t pos = textLen;
     if (args.hasDefined(1)) {
         if (args[1].isInt32()) {
             int i = args[1].toInt32();
             pos = (i < 0) ? 0U : uint32_t(i);
         } else {
             double d;
             if (!ToInteger(cx, args[1], &d))
                 return false;
             pos = uint32_t(Min(Max(d, 0.0), double(UINT32_MAX)));
         }
     }
 
-    // Step 6
-    const jschar *textChars = str->getChars(cx);
-    if (!textChars)
-        return false;
-
-    // Step 9
+    // Step 10
     uint32_t end = Min(Max(pos, 0U), textLen);
 
-    // Step 10
+    // Step 11
     uint32_t searchLen = searchStr->length();
     const jschar *searchChars = searchStr->chars();
 
-    // Step 12
+    // Step 13 (reordered)
     if (searchLen > end) {
         args.rval().setBoolean(false);
         return true;
     }
 
-    // Step 11
+    // Step 12
     uint32_t start = end - searchLen;
 
-    // Steps 13 and 14
+    // Steps 14 and 15
     args.rval().setBoolean(PodEqual(textChars + start, searchChars, searchLen));
     return true;
 }
 
 static bool
 js_TrimString(JSContext *cx, Value *vp, bool trimLeft, bool trimRight)
 {
     CallReceiver call = CallReceiverFromVp(vp);