Revision 1075880 of Temporary Installation in Firefox

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<div class="summary">
<p>This article describes how an add-on developer can temporarily install an add-on in Firefox for testing and debugging. The add-on will stay installed until you restart Firefox. You can use this method with any kind of restartless add-on, including <a href="/en-US/docs/Mozilla/Add-ons/Bootstrapped_extensions">bootstrapped extensions</a> and <a href="/en-US/docs/Mozilla/Add-ons/SDK">Add-on SDK add-ons</a>.</p>

<p>Note that this is <em>not</em> how end users should install add-ons in Firefox. End users will install add-ons by downloading and opening packaged add-ons that have been signed by Mozilla. To learn how a WebExtension developer can get such a packaged, signed add-on, see <a href="/en-US/docs/Mozilla/Add-ons/WebExtensions/Publishing_your_WebExtension">Publishing your WebExtension</a>.</p>
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<p>To install an add-on temporarily:</p>

<ul>
 <li>open Firefox</li>
 <li>enter "about:debugging" in the URL bar</li>
 <li>click "Load Temporary Add-on"</li>
 <li>open the add-on's directory and select any file inside the add-on.</li>
</ul>

<p>The add-on will be installed, and will stay installed until you restart Firefox.</p>

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<h2 id="Updating_a_temporary_add-on">Updating a temporary add-on</h2>

<p>If you install the add-on in this way, what happens when you update the add-on's files?</p>

<h3 id="Before_Firefox_48">Before Firefox 48</h3>

<ul>
 <li>If you change files that are loaded on demand, like <a href="/en-US/docs/Mozilla/Add-ons/WebExtensions/Content_scripts">content scripts</a> or <a href="/en-US/Add-ons/WebExtensions/Anatomy_of_a_WebExtension#Browser_actions_2">popups</a>, then changes you make are picked up automatically, and you'll see them the next time the content script is loaded or the popup is shown.</li>
 <li>If you change files that stay loaded the whole time, like <a href="/en-US/Add-ons/WebExtensions/Anatomy_of_a_WebExtension#Background_scripts">background scripts</a>, then you can pick up changes you've made by disabling and then re-enabling the add-on in the about:addons page.</li>
 <li>If you change files that are only parsed at install time, like the <a href="/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json">manifest.json</a> file, you'll need to restart Firefox, then load the add-on again.</li>
</ul>

<div class="note">
<p>Note that before Firefox 48, loading the add-on again by pressing "Load Temporary Add-on" without restarting Firefox <em>does not work</em>.</p>
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<h3 id="Firefox_48_onwards">Firefox 48 onwards</h3>

<ul>
</ul>

<p>From Firefox 48 onwards:</p>

<ul>
 <li>if you change files that are loaded on demand, like <a href="/en-US/docs/Mozilla/Add-ons/WebExtensions/Content_scripts">content scripts</a> or <a href="/en-US/Add-ons/WebExtensions/Anatomy_of_a_WebExtension#Browser_actions_2">popups</a>, then changes you make are picked up automatically, and you'll see them the next time the content script is loaded or the popup is shown.</li>
 <li>there's a better way to handle the other cases: click the "Reload" button next to the "Debug" button. This does what it says:
  <ul>
   <li>reloading any persistent scripts, such as <a href="/en-US/Add-ons/WebExtensions/Anatomy_of_a_WebExtension#Background_scripts">background scripts</a></li>
   <li>parsing the manifest.json file again, so changes to <code><a href="/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/permissions">permissions</a></code>, <code><a href="/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/content_scripts">content_scripts</a></code>, <code><a href="/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/browser_action">browser_action</a></code> or any other keys will take effect.</li>
  </ul>
 </li>
</ul>

<div class="note">
<p>Note that in Firefox 48 only, "Reload" does not update the add-on's name and description that are displayed in about:debugging and about:addons. This is fixed in Firefox 49.</p>
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