Revision 995393 of New in JavaScript 1.8.1

<div>{{jsSidebar("New_in_JS")}}</div>

<p>The following is a changelog for JavaScript 1.8.1. This version was included in <a href="/en-US/Firefox/Releases/3.5">Firefox 3.5</a>.</p>

<p>JavaScript 1.8.1 is a modest update syntactically to JavaScript; the main change in this release is the addition of the <a href="/en-US/docs/SpiderMonkey/Internals/Tracing_JIT" title="SpiderMonkey/Internals/Tracing JIT">Tracemonkey just-in-time compiler</a>, which improves performance.</p>

<h2 id="New_features_in_JavaScript_1.8.1">New features in JavaScript 1.8.1</h2>

<ul>
 <li>{{jsxref("Object.getPrototypeOf()")}}</li>
 <li><a href="/en-US/docs/Web/JavaScript/Guide/Using_native_JSON">Support for native JSON</a></li>
 <li>{{jsxref("String.prototype.trim()")}}</li>
 <li>{{jsxref("String.prototype.trimLeft()")}}</li>
 <li>{{jsxref("String.prototype.trimRight()")}}</li>
 <li>{{jsxref("String.prototype.startsWith()")}}</li>
</ul>

<h2 id="Changed_functionality_in_JavaScript_1.8.1">Changed functionality in JavaScript 1.8.1</h2>

<ul>
 <li>Implicit setting of properties in object and array initializers no longer execute setters in JavaScript. This makes the behavior of setting the values of properties more predictable.</li>
</ul>