path: root/files/es/mozilla/firefox/releases/68/index.html

---
title: Firefox 68 for developers
slug: Mozilla/Firefox/Releases/68
translation_of: Mozilla/Firefox/Releases/68
---
<p>{{FirefoxSidebar}}</p>

<p class="summary">This article provides information about the changes in Firefox 68 that will affect developers. Firefox 68 was released on July 9, 2019.</p>

<h2 id="Changes_for_web_developers">Changes for web developers</h2>

<h3 id="Developer_tools">Developer tools</h3>

<h4 id="Browserweb_console">Browser/web console</h4>

<ul>
 <li>The Web console now shows <a href="/en-US/docs/Tools/Web_Console/Console_messages#CSS">more information about CSS warnings</a>, including a node list of the DOM elements that used the rule ({{bug(1093953)}}).</li>
 <li>You can now filter content in the Web console using regular expressions ({{bug(1441079)}}).</li>
 <li>The Browser console now allows you to show or hide messages from the content process by setting or clearing the checkbox labeled <em>Show Content Messages</em> ({{bug(1260877)}}).</li>
</ul>

<h4 id="JavaScript_debugger">JavaScript debugger</h4>

<ul>
 <li>You can now <a href="/en-US/docs/Tools/Debugger/How_to/Search#Searching_in_all_files">Search</a> in all files in the current project from the debugger by pressing <kbd>Shift</kbd> + <kbd>Ctrl</kbd> + <kbd>F</kbd> (Windows or Linux) or <kbd>Shift</kbd> + <kbd>Cmd</kbd> + <kbd>F</kbd> (macOS) ({{bug(1320325)}}).</li>
</ul>

<h4 id="Network_monitor">Network monitor</h4>

<ul>
 <li>The Network monitor <a href="/en-US/docs/Tools/Network_Monitor/request_list#Filtering_requests">request list</a> now allows you to block a specific URL ({{bug(1151368)}}).</li>
 <li>You can now resend a network request without editing the method, URL, parameters, and headers, using the <a href="/en-US/docs/Tools/Network_Monitor/request_list#Context_menu">Resend</a> command on the context menu ({{bug(1422014)}}).</li>
 <li>The context menu of the Network monitor <a href="/en-US/docs/Tools/Network_Monitor/request_details#Headers">Headers</a> tab now allows you to copy all or some of the header information to the clipboard in JSON format ({{bug(1442249)}}).</li>
</ul>

<h4 id="Page_inspector">Page inspector</h4>

<ul>
 <li>A button has been added to the <a href="/en-US/docs/Tools/Page_Inspector/How_to/Examine_and_edit_CSS#Examine_CSS_rules">rules panel</a> of the Page inspector that allows you to toggle the display of any print media queries ({{bug(1534984)}}).</li>
 <li>The <a href="/en-US/docs/Tools/Page_Inspector/How_to/Edit_fonts">fonts panel</a> now includes a slider to modify <code>letter-spacing</code> ({{bug(1536237)}}).</li>
 <li>A warning icon appears next to unsupported CSS properties or rules that have invalid values, to help you understand why certain styles are not being applied ({{bug(1306054)}}).</li>
</ul>

<h4 id="Storage_inspector">Storage inspector</h4>

<ul>
 <li>You can now <a href="/en-US/docs/Tools/Storage_Inspector#Local_storage_Session_storage">delete local and session storage</a> entries by selecting the item in the storage inspector and pressing the backspace key ({{bug(1522893)}}).</li>
</ul>

<h4 id="Other">Other</h4>

<ul>
 <li>The <a href="/en-US/docs/Tools/Accessibility_inspector">Accessibility Inspector</a> now includes a new <em>Check for issues</em> feature, which will include a number of audit tools to highlight accessibility problems on your web pages. The first available check is <em>contrast</em>, for highlighting color contrast problems.</li>
 <li>The preference that controls the visibility of internal extensions (system add-ons and hidden extensions) on the <a href="/en-US/docs/Tools/about:debugging">about:debugging</a> page has been changed from <code>devtools.aboutdebugging.showSystemAddons</code> to <code>devtools.aboutdebugging.showHiddenAddons</code> ({{bug(1544372)}}).</li>
 <li><a href="/en-US/docs/Tools/Responsive_Design_Mode">Responsive design mode</a> has been redesigned — the <em>Device Settings</em> dialog (device selection menu &gt; <em>Edit List...</em>) is now more intuitive and simpler to use ({{bug(1487857)}}).</li>
</ul>

<h4 id="Removals">Removals</h4>

<ul>
 <li>The "Enable add-on debugging" checkbox has been removed from the <a href="/en-US/docs/Tools/about:debugging">about:debugging</a> page ({{bug(1544813)}}).</li>
</ul>

<h3 id="HTML">HTML</h3>

<ul>
 <li>The {{HTMLElement("track")}} element — represented by {{domxref("HTMLTrackElement")}} — now receives a {{domxref("HTMLTrackElement.cuechange_event", "cuechange")}} event in addition to the {{domxref("TextTrack")}} itself, if the text track is a contained by a media element ({{bug(1548731)}}).</li>
 <li>{{htmlelement("link")}} elements support the <code>disabled</code> attribute again, albeit with different behavior. When <code>disabled</code> is set on a <code>&lt;link&gt;</code> element along with <code>rel="stylesheet"</code>, the referenced stylesheet is not loaded during page load, and will be loaded on demand when the <code>disabled</code> attribute is changed to <code>false</code> or removed ({{bug(1281135)}}).</li>
</ul>

<h4 id="Removals_2"> Removals</h4>

<ul>
 <li><code><a href="/en-US/docs/Web/HTML/Element/meta">&lt;meta http-equiv="set-cookie"&gt;</a></code> is no longer supported ({{bug(1457503)}}).</li>
</ul>

<h3 id="CSS">CSS</h3>

<ul>
 <li><a href="/en-US/docs/Web/CSS/CSS_Scroll_Snap">CSS Scroll Snapping</a> has been updated to the latest version of the specification ({{bug(1312163)}}) and ({{bug(1544136)}}), this includes:

  <ul>
   <li>The <code>scroll-padding</code> properties ({{bug(1373832)}})</li>
   <li>The <code>scroll-margin</code> properties ({{bug(1373833)}})</li>
   <li>{{CSSxRef("scroll-snap-align")}} ({{bug(1373835)}})</li>
  </ul>
 </li>
 <li>The {{CSSxRef("-webkit-line-clamp")}} property has been implemented for compatibility with other browsers ({{bug(866102)}}).</li>
 <li>Support has been added for the {{CSSxRef("::marker")}} pseudo-element ({{bug(205202)}}) and animation for <code>::marker</code> pseudos ({{bug(1538618)}})</li>
 <li>We changed {{CSSxRef("currentColor")}} to be a computed value (except for the {{cssxref("color")}} property)  ({{bug(760345)}}).</li>
 <li>Support has been fixed for the <code>ch</code> length unit so it now matches the spec (fallback for no '0' glyph, vertical metrics) ({{bug(282126)}})</li>
 <li>The  {{CSSxRef("counter-set")}} property has been implemented. ({{bug(1518201)}}).</li>
 <li>We now implement list numbering using a built-in "list-item" counter; this fixes list numbering bugs ({{bug(288704)}}).</li>
 <li>Selector matching and parsing support has been implemented for <code><a href="/en-US/docs/Web/CSS/::part">::part()</a></code> ({{bug(1545430)}}) and ({{bug(1545425)}}).</li>
 <li><a href="/en-US/docs/Web/CSS/CSS_Transforms">CSS Transforms</a> are now supported in indirectly rendered things e.g.)  {{SVGElement("mask")}},  {{SVGElement("marker")}},  {{SVGElement("pattern")}},  {{SVGElement("clipPath")}} ({{bug(1323962)}}).</li>
 <li>
  <p>While we're keeping the prefixed versions of the various gradient properties ({{cssxref("linear-gradient")}}, {{cssxref("radial-gradient")}}, and {{cssxref("repeating-radial-gradient")}} available for compatibility reasons, we have revised how they're parsed so that they're handled much more like the non-prefixed versions. This means that certain existing styles won't work correctly.</p>

  <p>In particular, the complicated syntax taking both an angle and a position will no longer work, and the <code>to</code> keyword in the <code>&lt;side-or-corner&gt;</code> parameter is not required for the prefixed gradient properties. You are encouraged to use the standard, non-prefixed gradient properties instead, as they're now widely supported ({{bug(1547939)}}).</p>
 </li>
</ul>

<h4 id="Removals_3">Removals</h4>

<ul>
 <li>{{CSSxRef("scroll-snap-coordinate")}}, {{CSSxRef("scroll-snap-destination")}}, {{CSSxRef("scroll-snap-type-x")}} and {{CSSxRef("scroll-snap-type-y")}} have been removed.</li>
 <li>The {{CSSxRef("scroll-snap-type")}} property has become a longhand, so the old shorthand syntax like <code>scroll-snap-type:mandatory</code> will stop working. See the <a href="https://www.fxsitecompat.com/en-CA/docs/2019/legacy-css-scroll-snap-syntax-support-has-been-dropped/">Firefox Site Compatability</a> note.</li>
</ul>

<h3 id="SVG">SVG</h3>

<p><em>No changes.</em></p>

<h3 id="JavaScript">JavaScript</h3>

<ul>
 <li>The new {{jsxref("BigInt")}} primitive is enabled by default ({{bug(1527902)}}).</li>
</ul>

<h3 id="APIs">APIs</h3>

<h4 id="CSS_Object_Model_(CSSOM)">CSS Object Model (CSSOM)</h4>

<ul>
 <li>The legacy {{domxref("CSSStyleSheet.rules", "rules")}} property and {{domxref("CSSStyleSheet.addRule", "addRule()")}} and {{domxref("CSSStyleSheet.removeRule", "removeRule()")}} methods have been added to the {{domxref("CSSStyleSheet")}} interface. These were introduced by Internet Explorer 9 and have never managed to quite be stamped out, so they have been added to improve compatibility with the small percentage of sites that still use them ({{bug(1545823)}}).</li>
</ul>

<h4 id="DOM">DOM</h4>

<ul>
 <li>The <a href="/en-US/docs/Web/API/Visual_Viewport_API">Visual Viewport API</a> has now been enabled by default on Android ({{bug(1512813)}}). Adding this API to desktop versions of Firefox is being tracked in {{bug(1551302)}}.</li>
 <li>The {{domxref("Window")}} feature <code><a href="/en-US/docs/Web/API/Window/open#noreferrer">noreferrer</a></code> is now supported; if specified, the new window's content is loaded without sharing the hostname, IP address, URL, or other identifying information about the host device ({{bug(1527287)}}).</li>
 <li>The {{domxref("HTMLImageElement.decode", "decode()")}} method on <code>HTMLImageElement</code> is now implemented. This can be used to trigger loading and decoding of an image prior to adding it to the DOM ({{bug(1501794)}}).</li>
 <li>{{domxref("XMLHttpRequest")}} has been updated to no longer accept the non-standard <code>moz-chunked-arraybuffer</code> value for {{domxref("XMLHttpRequest.responseType", "responseType")}}. Code still using it should be updated to <a href="/en-US/docs/Web/API/Streams_API/Using_readable_streams#Consuming_a_fetch_as_a_stream">use the Fetch API as a stream</a> ({{bug(1120171)}}).</li>
 <li><code>XMLHttpRequest</code> now outputs a warning to console if you perform a synchronous request while handling an {{domxref("Window.unload_event", "unload")}}, {{domxref("Window.beforeunload_event", "beforeunload")}}, or {{domxref("Window.pagehide_event", "pagehide")}} event ({{bug(980902)}}).</li>
 <li>The {{domxref("Document.cookie", "cookie")}} property has moved from the {{domxref("HTMLDocument")}} interface to the {{domxref("Document")}} interface, allowing documents other than {{Glossary("HTML")}} to use cookies ({{bug(144795)}}).</li>
 <li>The {{domxref("HTMLElement.focus()")}} and {{domxref("SVGElement.focus()")}} methods now accept an optional object that may contain a boolean <code>preventScroll</code> option specifying whether or not to block the browser from scrolling the newly-focused element into view ({{bug(1374045)}}).</li>
</ul>

<h4 id="DOM_events">DOM events</h4>

<ul>
 <li><a href="/en-US/docs/Mozilla/Firefox_for_Android">Firefox for Android</a> no longer incorrectly sends a {{domxref("Window.resize_event", "resize")}} event until after the first frame is painted; this improves web compatibility with sites that don't expect this event to occur ({{bug(1528052)}}).</li>
 <li>The dispatching of events for non-primary mouse buttons has been made to more closely follow the specification; the {{domxref("Element.click_event", "click")}} event is no longer sent when non-primary buttons are clicked, instead using {{domxref("Element.auxclick_event", "auxclick")}}. In addition, {{domxref("Element.dblclick_event", "dblclick")}} no longer fires for non-primary buttons ({{bug(1379466)}}).</li>
 <li>The proprietary {{domxref("MouseEvent.mozPressure")}} property has been deprecated, and will now trigger a warning in the console ({{bug(1165211)}}).</li>
</ul>

<h4 id="Media_Web_Audio_and_WebRTC">Media, Web Audio, and WebRTC</h4>

<ul>
 <li>WebRTC has been updated to recognize that a <code>null</code> candidate passed into the {{domxref("RTCPeerConnection.icecandidate", "icecandidate")}} event handler, indicating the receipt of a candidate, instead indicates that there are no further candidates coming; when this happens the ICE gathering ({{domxref("RTCPeerConnection.iceGatheringState", "iceGatheringState")}}) state reaches <code>complete</code> ({{bug(1318167)}}).</li>
 <li>The {{domxref("RTCRtpReceiver")}} methods {{domxref("RTCRtpReceiver.getContributingSources", "getContributingSources()")}} and {{domxref("RTCRtpReceiver.getSynchronizationSources", "getSynchronizationSources()")}} now support video tracks; previously they only worked on audio ({{bug(1534466)}}).</li>
 <li>The Web Audio API {{domxref("MediaStreamTrackAudioSourceNode")}} interface is now supported, as is the method {{domxref("AudioContext.createMediaStreamTrackSource()")}} ({{bug(1324548)}}).</li>
 <li>{{domxref("RTCDataChannel.negotiated")}} is now implemented ({{bug(1529695)}}).</li>
 <li>The {{domxref("MediaStreamAudioSourceNode.MediaStreamAudioSourceNode", "MediaStreamAudioSourceNode()")}} constructor has been updated to match the current specification's definition that the "first audio track" in the stream is the track whose ID comes first in lexicographical order ({{bug(1324548)}}).</li>
 <li>
  <p>{{domxref("MediaDevices.getUserMedia", "getUserMedia()")}} may no longer be used from a non-secure context; attempting to do so now throws a <code>NotAllowedError</code> exception. Secure contexts are those loaded using HTTPS, those located using the <code>file:///</code> scheme, and those loaded from <code>localhost</code>. For now, if you must, you can re-enable the ability to perform insecure calls to <code>getUserMedia()</code> by setting the preference <code>media.getusermedia.insecure.enabled</code> to <code>true</code> ({{bug(1335740)}}).</p>

  <div class="blockIndicator note">
  <p><strong>Note:</strong> In the future, Firefox will also remove the {{domxref("navigator.mediaDevices")}} property on insecure contexts, preventing all access to the {{domxref("MediaDevices")}} APIs. <strong>This is already the case in Nightly builds.</strong></p>
  </div>
 </li>
</ul>

<h4 id="Removals_4">Removals</h4>

<ul>
 <li>Removed the non-standard {{DOMxRef("XMLDocument.load()")}} method ({{bug(332175)}}).</li>
 <li>Removed the non-standard {{DOMxRef("XMLDocument.async")}} property ({{bug(1328138)}}).</li>
 <li>The {{domxref("RTCIceCredentialType")}} <code>token</code> value has been removed ({{bug(1529595)}}).</li>
</ul>

<h3 id="HTTP">HTTP</h3>

<ul>
 <li>The <a href="/en-US/docs/Web/HTTP">HTTP</a> {{HTTPHeader("Clear-Site-Data")}} header no longer supports the <code>executionContexts</code> directive. This was removed due to problems with interactions between interconnections among different kinds of data at different points in the navigation process and the way the specification is designed. It <a href="https://github.com/w3c/webappsec-clear-site-data/issues/59">has been proposed</a> that this directive be removed from the specification for this reason, among others ({{bug(1548034)}}).</li>
</ul>

<h4 id="Removals_5">Removals</h4>

<ul>
 <li>The {{HTTPHeader("Content-Security-Policy")}} directive <code>require-sri-for</code> is no longer supported due to concerns about its standardization status. It was previously available only behind a preference, which was off by default ({{bug(1386214)}}).</li>
</ul>

<h3 id="Security">Security</h3>

<p><em>No changes.</em></p>

<h3 id="WebDriver_conformance_(Marionette)">WebDriver conformance (Marionette)</h3>

<h4 id="Bug_fixes">Bug fixes</h4>

<ul>
 <li>If <code>WebDriver:SwitchToWindow</code> changes the selection to a different window it now waits for its <code>focus</code> and <code>activate</code> events before returning ({{bug(1335085)}}).</li>
 <li>Fixed the <code>TypeError: this.tabModal is null</code> failure, which sometimes appeared when interacting with modal dialogs or user prompts ({{bug(1538782)}})</li>
</ul>

<h4 id="Other_2">Other</h4>

<ul>
 <li>Disabled the feature to force unloading background tabs on low memory conditions, to prevent top-level browser contexts from magically disappearing ({{bug(1553748)}}).</li>
 <li>Disabled priviledged content processes that caused HTTP authentication dialogs not to appear when navigating to a website after opening a new tab ({{bug(1558763)}}).</li>
</ul>

<h3 id="Plugins">Plugins</h3>

<p><em>No changes.</em></p>

<h2 id="Changes_for_add-on_developers">Changes for add-on developers</h2>

<h3 id="API_changes">API changes</h3>

<ul>
 <li>The The <code>proxy.register()</code> and <code>proxy.unregister()</code> functions have been deprecated and will be removed from Firefox 71 ({{bug(1545811)}}).</li>
 <li>When an add-on attempts to add a bookmark folder to the root folder, the resulting error message is now much more intuitive ({{bug(1512171)}}).</li>
 <li>The promise returned by <code><a href="/en-US/docs/Mozilla/Add-ons/WebExtensions/API/tabs/duplicate">browser.tabs.duplicate()</a></code> now resolves immediately, before the tabs are completely loaded, to improve performance ({{bug(1394376)}}).</li>
 <li>Support has been added for chrome.storage.managed, allowing web extension settings to be implemented via enterprise policy ({{bug(1230802)}}).</li>
 <li>There is now a Group Policy option to blacklist <em>all</em> extensions except the ones that have been whitelisted ({{bug(1522823)}}).</li>
</ul>

<h3 id="Manifest_changes">Manifest changes</h3>

<p><em>No changes.</em></p>

<h2 id="See_also">See also</h2>

<ul>
 <li><a href="https://www.fxsitecompat.com/en-CA/versions/68/">Site compatibility for Firefox 68</a></li>
</ul>

<h2 id="Older_versions">Older versions</h2>

<p>{{Firefox_for_developers(67)}}</p>