Site Compatibility for Firefox 27

  • Revision slug: Mozilla/Firefox/Releases/27/Site_Compatibility
  • Revision title: Site Compatibility for Firefox 27
  • Revision id: 485433
  • Created:
  • Creator: Yoshino
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{{ draft() }}

Firefox 27 Aurora (pre-Beta) was released on . While it has been developed to maintain compatibility as much as possible, the new version includes some changes affecting backward compatibility aimed at improving interoperability with the other browsers or following the latest Web standards. Here's the list of such changes — hope this helps whenever you test your sites or applications.

This article only explains the changes that may affect backward compatibility for websites. For the other new features and changes, please read the following documents:

This list may be updated until the release of the final version on , so please check back later. Follow @MozWebCompat on Twitter for further updates.

CSS

-moz-grab and -moz-grabbing have been unprefixed

The unprefixed support of -moz-grab and -moz-grabbing keywords for the {{ cssxref("cursor") }} property has been added. Those prefixed keywords will be removed after a reasonable period of time.

-moz-rgba() and -moz-hsla() have been dropped

The support of the prefixed -moz-rgba() and -moz-hsla() functional notations for color values has been removed. The standard, unprefixed rgba() and hsla() notations should be used instead.

Curly brackets are no longer allowed in style attributes

Previously, in Firefox Quirks mode, the CSS parser allowed curly brackets around the contents of style attributes like <div style="{ color: blue; }">. This behavior has been removed from Firefox 27 for interoperability.

DOM

As part of the ongoing effort to standardize global objects, the non-standard stylesheet change event interfaces, including StyleRuleChangeEvent, StyleSheetApplicableStateChangeEvent and StyleSheetChangeEvent, are no longer available from Web content. The CSSGroupRuleRuleList interface, the implementation detail of {{ domxref("CSSRuleList") }}, has also been removed.

atob now ignores whitespaces

The {{ domxref("window.atob") }} method, that decodes a Base64-encoded string, has been updated to ignore all space characters in the argument to comply with the latest HTML5 spec.

JavaScript

The iterator implementation has been updated to the latest spec

The implementation of the iterator and for...of loop has been updated to comply with the ECMAScript 6 spec. The iterator method of the Array, Map, Set and String interfaces has been renamed to @@iterator. Previously, the next method of an iterator returned a value from the array (or a key-value pair from the object), and raised a StopIteration exception when the iteration was done. The next method now returns an object like { done: false, value:  value  } then returns { done: true, value: undefined } when the iteration is done.

Networking

SPDY/2 support has been dropped

The support of SPDY Protocol Draft 2 has been removed. Web sites should upgrade to SPDY/3 or 3.1.

WebGL

Prefixed extensions have been deprecated

MOZ_ prefixed WebGL extension strings are now deprecated. Support for them will be removed in the future. Use unprefixed extension strings instead.

Revision Source

<p>{{ draft() }}</p>
<p>Firefox&nbsp;27 <a href="http://www.mozilla.org/en-US/firefox/aurora/">Aurora</a> (pre-Beta) was released on <time datetime="2013-11-01">November&nbsp;1, 2013</time>. While it has been developed to maintain compatibility as much as possible, the new version includes some changes affecting backward compatibility aimed at improving interoperability with the other browsers or following the latest Web standards. Here's the list of such changes — hope this helps whenever you test your sites or applications.</p>
<p><strong>This article only explains the changes that may affect backward compatibility for websites</strong>. For the other new features and changes, please read the following documents:</p>
<ul>
 <li><a href="http://www.mozilla.org/en-US/firefox/27.0a2/auroranotes/">Firefox&nbsp;27 Aurora Release Notes</a></li>
 <li><a href="/en-US/docs/Mozilla/Firefox/Releases/27">Firefox&nbsp;27 for developers</a></li>
</ul>
<p>This list may be updated until the release of the final version on <time datetime="2014-01-21">January&nbsp;21, 2014</time>, so please check back later. Follow <a href="https://twitter.com/MozWebCompat">@MozWebCompat</a> on Twitter for further updates.</p>
<section id="sect1">
 <h2 id="CSS">CSS</h2>
 <section id="sect2">
  <h3 id="-moz-grab_and_-moz-grabbing_have_been_unprefixed"><code>-moz-grab</code> and <code>-moz-grabbing</code> have been unprefixed</h3>
  <ul>
   <li><a href="https://bugzilla.mozilla.org/show_bug.cgi?id=880672">Bug&nbsp;880672 – Unprefix -moz-grab and -moz-grabbing</a></li>
  </ul>
  <p>The unprefixed support of <code>-moz-grab</code> and <code>-moz-grabbing</code> keywords for the {{ cssxref("cursor") }} property has been added. Those prefixed keywords will be removed after a reasonable period of time.</p>
 </section>
 <section id="sect3">
  <h3 id="-moz-rgba()_and_-moz-hsla()_have_been_dropped"><code>-moz-rgba()</code> and <code>-moz-hsla()</code> have been dropped</h3>
  <ul>
   <li><a href="https://bugzilla.mozilla.org/show_bug.cgi?id=893319">Bug&nbsp;893319 – remove -moz-rgba() and -moz-hsla()</a></li>
  </ul>
  <p>The support of the prefixed <code>-moz-rgba()</code> and <code>-moz-hsla()</code> functional notations for <a href="/en-US/docs/Web/CSS/color_value">color values</a> has been removed. The standard, unprefixed <code>rgba()</code> and <code>hsla()</code> notations should be used instead.</p>
 </section>
 <section id="sect4">
  <h3 id="Curly_brackets_are_no_longer_allowed_in_style_attributes">Curly brackets are no longer allowed in <code>style</code> attributes</h3>
  <ul>
   <li><a href="https://bugzilla.mozilla.org/show_bug.cgi?id=915053">Bug&nbsp;915053 – remove quirk allowing {} around style attribute</a></li>
  </ul>
  <p>Previously, in Firefox <a href="/en-US/docs/Mozilla_Quirks_Mode_Behavior">Quirks mode</a>, the CSS parser allowed curly brackets around the contents of <code>style</code> attributes like <code>&lt;div&nbsp;style="{&nbsp;color:&nbsp;blue;&nbsp;}"&gt;</code>. This behavior has been removed from Firefox&nbsp;27 for interoperability.</p>
 </section>
</section>
<section id="sect5">
 <h2 id="DOM">DOM</h2>
 <section id="sect6">
  <h3 id="Some_CSS-related_interfaces_have_been_removed">Some CSS-related interfaces have been removed</h3>
  <ul>
   <li><a href="https://bugzilla.mozilla.org/show_bug.cgi?id=872934">Bug&nbsp;872934 – convert style sheet change event interfaces to Web IDL and stick [NoInterfaceObject] on them</a></li>
   <li><a href="https://bugzilla.mozilla.org/show_bug.cgi?id=916871">Bug&nbsp;916871 – Remove classinfo bits for CSSGroupRuleRuleList</a></li>
  </ul>
  <p>As part of the ongoing effort to standardize global objects, the non-standard stylesheet change event interfaces, including <code>StyleRuleChangeEvent</code>, <code>StyleSheetApplicableStateChangeEvent</code> and <code>StyleSheetChangeEvent</code>, are no longer available from Web content. The <code>CSSGroupRuleRuleList</code> interface, the implementation detail of {{ domxref("CSSRuleList") }}, has also been removed.</p>
 </section>
 <section id="sect7">
  <h3 id="atob_now_ignores_whitespaces"><code>atob</code> now ignores whitespaces</h3>
  <ul>
   <li><a href="https://bugzilla.mozilla.org/show_bug.cgi?id=711180">Bug&nbsp;711180 – atob should ignore whitespace</a></li>
  </ul>
  <p>The {{ domxref("window.atob") }} method, that decodes a Base64-encoded string, has been updated to ignore all space characters in the argument to comply with the latest HTML5 spec.</p>
 </section>
</section>
<section id="sect8">
 <h2 id="JavaScript">JavaScript</h2>
 <section id="sect9">
  <h3 id="The_iterator_implementation_has_been_updated_to_the_latest_spec">The iterator implementation has been updated to the latest spec</h3>
  <ul>
   <li><a href="https://bugzilla.mozilla.org/show_bug.cgi?id=907077">Bug&nbsp;907077 – Hide the "iterator"-based for-of customization from web content</a></li>
  </ul>
  <p>The implementation of the <a href="/en-US/docs/Web/JavaScript/Guide/Iterators_and_Generators"><code>iterator</code></a> and <a href="/en-US/docs/Web/JavaScript/Reference/Statements/for...of"><code>for...of</code> loop</a> has been updated to comply with the ECMAScript&nbsp;6 spec. The <code>iterator</code> method of the <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array"><code>Array</code></a>, <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map"><code>Map</code></a>, <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set"><code>Set</code></a> and <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/String"><code>String</code></a> interfaces has been renamed to <code>@@iterator</code>. Previously, the <code>next</code> method of an iterator returned a value from the array (or a key-value pair from the object), and raised a <code>StopIteration</code> exception when the iteration was done. The <code>next</code> method now returns an object like <code>{&nbsp;done:&nbsp;false,&nbsp;value:&nbsp;
   <i>
    value</i>
   &nbsp;}</code> then returns <code>{&nbsp;done:&nbsp;true,&nbsp;value:&nbsp;undefined&nbsp;}</code> when the iteration is done.</p>
 </section>
</section>
<section id="sect10">
 <h2 id="Networking">Networking</h2>
 <section id="sect11">
  <h3 id="SPDY.2F2_support_has_been_dropped">SPDY/2 support has been dropped</h3>
  <ul>
   <li><a href="https://bugzilla.mozilla.org/show_bug.cgi?id=912550">Bug&nbsp;912550 – remove spdy/2 support</a></li>
  </ul>
  <p>The support of SPDY Protocol Draft&nbsp;2 has been removed. Web sites should upgrade to SPDY/3 or 3.1.</p>
 </section>
</section>
<section id="sect12">
 <h2 id="WebGL">WebGL</h2>
 <section id="sect13">
  <h3 id="Prefixed_extensions_have_been_deprecated">Prefixed extensions have been deprecated</h3>
  <ul>
   <li><a href="https://bugzilla.mozilla.org/show_bug.cgi?id=924176">Bug&nbsp;924176 – Warn on prefixed WebGL extensions usage (deprecated)</a></li>
  </ul>
  <p><code>MOZ_</code> prefixed WebGL <a href="/en-US/docs/Web/WebGL/Using_Extensions">extension strings</a> are now deprecated. Support for them will be removed in the future. Use unprefixed extension strings instead.</p>
 </section>
</section>
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