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How to disable firefox’s fullscreen warning message

How to disable firefox’s fullscreen warning message

How to Disable Firefox’s Fullscreen Warning Message

Whenever you fullscreen a video in Mozilla Firefox, a warning message appears for a few seconds and then slides off the screen.

While its primary purpose is for security, you might want to disable the popup if you find it annoying.

Let’s get started!

What Is the Fullscreen Warning, and Why Is It Important?

All modern browsers use the Fullscreen API to present desired content—such as videos, pictures, and online games—using the entire screen, void of other user interface elements.

When enabled, a small warning message momentarily appears at the top of the page, notifying you it has been triggered.

This is the same functionality when you watch a YouTube video in fullscreen mode.

How to disable firefox’s fullscreen warning message

While it can be annoying at times—and before you go ahead and disable the message altogether— it’s important to review its purpose and how it helps prevent phishing attacks.

The only real restriction for developers using the API is that in order to trigger fullscreen mode, the user must initiate it with a click or a keypress (keyboard shortcut).

The reason this condition exists is to prevent sketchy sites from automatically loading a phishing scam into fullscreen when visiting a site.

Unfortunately, this feature is susceptible to a very ingenious phishing attack. Attackers can use the API to show you a fake version of a website in fullscreen mode that looks surprisingly similar to the real deal.

All you need to do is click a legitimate-looking link, and the API loads fullscreen mode with what looks like a working web browser.

In this case, when the fake site goes to fullscreen mode, the browser flashes a warning message notifying you it has been triggered. If you miss the warning, you might think it’s a legit site.

If you want to know more about how the HTML5 Fullscreen API can be used in phishing attacks, Feross, a programmer who first discovered this, goes into great detail—and even has a working example of a fake Bank of America site—on their website.

So, now that we got all that out of the way, if you still want to disable the warning—or just reduce the time it takes to disappear—let’s continue.

How to Disable the Fullscreen Warning Message

To move forward and disable the fullscreen warning message, we’ll need to access the Advanced Preferences page, which is similar to enabling flags in Google Chrome.

Warning: Mozilla Firefox stores every setting on this page, so you have to be careful when tinkering around here.

Changing these settings can be harmful to the stability and security of the browser.

You should only continue if you’re confident and sure of what you’re doing.

Type about:config into the address bar and then hit the Enter key.

The page loads with a warning about the impacts of changing these preferences and the effect it can have on Firefox.

Click the “Accept the Risk and Continue” button.

How to disable firefox’s fullscreen warning message

In the search bar, type full-screen-api.warning.timeout into the search bar and click the pencil icon next to the result to change the value of the preference.

How to disable firefox’s fullscreen warning message

The number you enter is the amount of time in milliseconds until the warning starts to disappear.

Keep in mind that anything under 500 barely appears after fullscreen is initiated.

For security reasons, if you want to be able to see the warning when entering the fullscreen mode, you should put something around 500 milliseconds.

Otherwise, enter 0.

Click the checkmark when you finish.

How to disable firefox’s fullscreen warning message

After you change the value in the setting, you don’t need to restart Firefox.

The next time you click a video into fullscreen mode, the new timeout will be used.

To revert back to the default timeout, head back to the “Advanced Preferences” page and click the reset arrow on the far right of the full-screen-api.warning.timeout setting.

How to disable firefox’s fullscreen warning message

As mentioned before, there are security risks to completely disabling the warning message as some known phishing scams can prey on this vulnerability.

While this threat still exists, it’s probably wise to keep a timeout delay that notifies you when anything triggers fullscreen mode in the browser.

Conclusion

I hope I helped you disable the full-screen API warning on Mozilla Firefox.

Remember to share this article with your friends, and on your preferred social networks.

How to disable firefox’s fullscreen warning message

Whenever you fullscreen a video in Firefox, a warning message appears for a few seconds and then slides off the screen. While its primary purpose is for security, you might want to disable the popup if you find it annoying.

What Is the Fullscreen Warning, and Why Is It Important?

All modern browsers use the Fullscreen API to present desired content—such as videos, pictures, and online games—using the entire screen, void of other user interface elements. When enabled, a small warning message momentarily appears at the top of the page, notifying you it has been triggered. This is the same functionality when you watch a YouTube video in fullscreen mode.

How to disable firefox’s fullscreen warning message

While it can be annoying at times—and before you go ahead and disable the message altogether— it’s important to review its purpose and how it helps prevent phishing attacks.

The only real restriction for developers using the API is that in order to trigger fullscreen mode, the user must initiate it with a click or a keypress (keyboard shortcut). The reason this condition exists is to prevent sketchy sites from automatically loading a phishing scam into fullscreen when visiting a site.

Unfortunately, this feature is susceptible to a very ingenious phishing attack. Attackers can use the API to show you a fake version of a website in fullscreen mode that looks surprisingly similar to the real deal. All you need to do is click a legitimate-looking link, and the API loads fullscreen mode with what looks like a working web browser.

In this case, when the fake site goes to fullscreen mode, the browser flashes a warning message notifying you it has been triggered. If you miss the warning, you might think it’s a legit site.

If you want to know more about how the HTML5 Fullscreen API can be used in phishing attacks, Feross, a programmer who first discovered this, goes into great detail—and even has a working example of a fake Bank of America site—on their website.

So, now that we got all that out of the way, if you still want to disable the warning—or just reduce the time it takes to disappear—let’s continue.

How to Disable the Fullscreen Warning Message

To move forward and disable the fullscreen warning message, we’ll need to access the Advanced Preferences page, which is similar to enabling flags in Chrome.

Warning: Firefox stores every setting on this page, so you have to be careful when tinkering around here. Changing these settings can be harmful to the stability and security of the browser. You should only continue if you’re confident and sure of what you’re doing.

Type about:config into the address bar and then hit the Enter key. The page loads with a warning about the impacts of changing these preferences and the effect it can have on Firefox. Click the “Accept the Risk and Continue” button.

How to disable firefox’s fullscreen warning message

In the search bar, type full-screen-api.warning.timeout into the search bar and click the pencil icon next to the result to change the value of the preference.

How to disable firefox’s fullscreen warning message

The number you enter is the amount of time in milliseconds until the warning starts to disappear. Keep in mind that anything under 500 barely appears after fullscreen is initiated. For security reasons, if you want to be able to see the warning when entering the fullscreen mode, you should put something around 500 milliseconds. Otherwise, enter 0. Click the checkmark when you finish.

How to disable firefox’s fullscreen warning message

After you change the value in the setting, you don’t need to restart Firefox. The next time you click a video into fullscreen mode, the new timeout will be used.

To revert back to the default timeout, head back to the “Advanced Preferences” page and click the reset arrow on the far right of the full-screen-api.warning.timeout setting.

How to disable firefox’s fullscreen warning message

As mentioned before, there are security risks to completely disabling the warning message as some known phishing scams can prey on this vulnerability. While this threat still exists, it’s probably wise to keep a timeout delay that notifies you when anything triggers fullscreen mode in the browser.

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  • How to Disable ‘is Now Fullscreen’ Warning Message on Firefox.

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Learn how to quickly and easily remove the annoying notice that Firefox shows whenever you make something go fullscreen. Remove the ‘is now fullscreen’ message shown in Firefox whenever something goes full-screen.

How to disable firefox’s fullscreen warning message

Of all the Internet browsers on the market, Firefox is by far the most customisable and privacy-conscious. It’s also one of the most continuously developed and active in the wider online community, with a constant focus on what users want and need. As a result, Firefox has become a very desirable browser for those less trusting of Google and Chrome.

Firefoxes customisation allows for quite a lot of change, including the ability to remove some of the browsers less important notifications. One of which this article aims to deal with today, the ‘is now in full-screen’ message. Following the instructions shown in this guide will allow you to completely remove the annoy notification from your browser.

How Do You Remove the ‘is now fullscreen’ Message When Making Something Fullscreen on Firefox?

To begin, you’ll first need to access Firefox’s Advanced Options page ‘aka’ the about:config page. To do this open Firefox, then type about:config into the address bar and press Enter. After you have accepted the warning prompt (only appears on your first access of about:config per browser installation) use the Search bar to search:

When the entry appears, click the pencil icon (edit) to the far right of the screen. The default value will be 3000, however, changing this to 0 will completely remove the ‘is now fullscreen’ prompt. Once you’ve made the change click the Tick to save it then Restart Firefox and the message will be gone. Alternatively, you can simply reduce the amount of time it is displayed by changing the figure to a smaller amount somewhere above 0.

On a Side Note…

If you have a USB device that always shows an error like either of the following:

“The last USB device you connected to this computer malfunctioned and Windows does not recognise it”

“There might be a problem with some files on this device or disc. This can happen if you remove the device or disc before all files have been written to it. “Scan and Fix (Recommended) or “Continue without scanning”

Make sure you check out the following article which will guide you through the process for disabling USB notifications on Windows 10.

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How to disable firefox’s fullscreen warning message

How do disable the new Fullscreen message?

  • 3 replies
  • 3 have this problem
  • 5282 views
  • Last reply by jscher2000

How to disable firefox’s fullscreen warning message

My UserChrome.css is edited to block the message when using fullscreen. The new update has a new fullscreen message, and ignores the code written in the UserChrome.css.

I am currently using this code, (its no longer working):

  1. full-screen-warning-container

Modified December 22, 2015 at 1:38:37 PM PST by TBSdota

Chosen solution

As you may know, the purpose of this is to alert you that the site has invoked full screen in case you were not expecting that to happen, since evil sites may use full screen to emulate a site you trust.

This full screen message changed in Firefox 43, and there are some new settings which control how soon and how long the message is displayed. Probably of most interest to you if you never want to see the warning is the following:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.

(2) In the search box above the list, type or paste FULL- and pause while the list is filtered

(3) Double-click the full-screen-api.warning.timeout preference and enter the display time. For example:

  • 3000 => displays for 3 seconds (default)
  • 500 => displays for 1/2 second
  • 0 => no display at all

Read this answer in context 👍 8

All Replies (3)

Chosen Solution

As you may know, the purpose of this is to alert you that the site has invoked full screen in case you were not expecting that to happen, since evil sites may use full screen to emulate a site you trust.

This full screen message changed in Firefox 43, and there are some new settings which control how soon and how long the message is displayed. Probably of most interest to you if you never want to see the warning is the following:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.

(2) In the search box above the list, type or paste FULL- and pause while the list is filtered

(3) Double-click the full-screen-api.warning.timeout preference and enter the display time. For example:

  • 3000 => displays for 3 seconds (default)
  • 500 => displays for 1/2 second
  • 0 => no display at all

Like any other browser, whenever you play video in full-screen mode or run something which takes up the whole screen, Firefox warns about it. The message is displayed for a few seconds before it disappears. If you find that annoying, then in this post, we will share how you can disable Firefox’s Fullscreen warning message.

How to disable firefox’s fullscreen warning message

Why does Firefox display a fullscreen warning message?

You may see a message like:

  • You are now fullscreen
  • Website is now full screen.

The Fullscreen API is allowed to be activated when a use initiates it. It can either be using the keyboard or with a mouse click. The API allows the website to offer a different version of the website or the player which fits the full-screen method. This mode can be used by a phishing website to automatically go full screen, and offer an interface that may look similar to the real website.

Remember that is this different from the F11 function or full-screen mode of Firefox. Here we are talking about video players or anything similar which goes full screen when users press a shortcut or use the mouse.

Disable Fullscreen warning message in Firefox

We will need to access the Advanced Preferences Page, also popularly called the configuration page. These pages are usually not entertained to be used by everyone, and make the changes carefully. If you change the wrong setting, you will have to reset the browser and may lose all your profiles.

How to disable firefox’s fullscreen warning message

  1. Open a new tap, and type about:config into the address bar followed by pressing the Enter key
  2. The page that loads next will warn you about the result of changing the core preferences. Click on the “Accept the Risk and Continue” button.
  3. In the next screen, use the search bar to find full-screen-api.warning.timeout
  4. When it shows up, click on the pencil icon next to the setting to edit the value
  5. The value the setting accepts is in milliseconds. You can set the value as Zero to disable it completely.

How to disable firefox’s fullscreen warning message

However, if you want to reduce the amount of time it stays, you will have to experiment a bit to it figure out. I will suggest keeping the timing such that you get to at least view for a second. It will help if you unluckily land on a bogus website.

Once done, next time you go full screen on a video, you will not see any warning.

That said, if you would like to revert, go back to the same setting and click on the reset arrow to revert to the default value.

Like any other browser, whenever you play video in full-screen mode or run something which takes up the whole screen, Firefox warns about it. The message is displayed for a few seconds before it disappears. If you find that annoying, then in this post, we will share how you can disable Firefox’s Fullscreen warning message.

How to disable firefox’s fullscreen warning message

Why does Firefox display a fullscreen warning message?

You may see a message like:

  • You are now fullscreen
  • Website is now full screen.

The Fullscreen API is allowed to be activated when a use initiates it. It can either be using the keyboard or with a mouse click. The API allows the website to offer a different version of the website or the player which fits the full-screen method. This mode can be used by a phishing website to automatically go full screen, and offer an interface that may look similar to the real website.

Remember that is this different from the F11 function or full-screen mode of Firefox. Here we are talking about video players or anything similar which goes full screen when users press a shortcut or use the mouse.

Disable Fullscreen warning message in Firefox

We will need to access the Advanced Preferences Page, also popularly called the configuration page. These pages are usually not entertained to be used by everyone, and make the changes carefully. If you change the wrong setting, you will have to reset the browser and may lose all your profiles.

How to disable firefox’s fullscreen warning message

  1. Open a new tap, and type about:config into the address bar followed by pressing the Enter key
  2. The page that loads next will warn you about the result of changing the core preferences. Click on the “Accept the Risk and Continue” button.
  3. In the next screen, use the search bar to find full-screen-api.warning.timeout
  4. When it shows up, click on the pencil icon next to the setting to edit the value
  5. The value the setting accepts is in milliseconds. You can set the value as Zero to disable it completely.

How to disable firefox’s fullscreen warning message

However, if you want to reduce the amount of time it stays, you will have to experiment a bit to it figure out. I will suggest keeping the timing such that you get to at least view for a second. It will help if you unluckily land on a bogus website.

Once done, next time you go full screen on a video, you will not see any warning.

That said, if you would like to revert, go back to the same setting and click on the reset arrow to revert to the default value.

  • Log in
  • Register
  • Home
  • News
  • How to Disable ‘is Now Fullscreen’ Warning Message on Firefox.

Related news

  • How to only view preferences you’ve modified in about:config on Firefox.
  • How to skip or bypass wait times for downloads. Link Bypassers
  • How to get Parental Controls for your Internet browser.
  • How to disable sponsored top sites on Firefox. Disable top site ads on Firefox.
  • How to add notes and comments to PDF files using Microsoft Edge.
  • How to force close duplicate and near-duplicate tabs in Chrome and Firefox.
  • How to bookmark specific sections of a website.
  • How to stop users from installing Add-ons in Firefox. Block access to extensions in Firefox.
  • How to Export Passwords From Microsoft Edge. (Transfer Save Passwords From Edge)
  • How to Use Firefox Private Relay on Firefox to Avoid Spam and Malicious Content.
  • How to Disable Detaching Tabs on Firefox. Stop Accidentally Detaching Tabs on Firefox.
  • How to Restore the Old Firefox Address Bar? Remove Firefox Awesome Bar.
  • How to Play Two Videos Side By Side With Synced Controls.
  • How to Stop Your Windows 10 Computer Shutting Down When Gaming or Watching Videos.
  • How to Add a Calendar, Notes, or a ‘To Do’ List to the New Tab Page of Firefox, Chrome or Edge

Related files

  • Mozilla Firefox
  • DivX Free (Windows)
  • Yahoo! Toolbar for Mozilla Firefox
  • Zwei-Stein Video Editor
  • PotPlayer
  • ZC Video Converter
  • Auslogics Browser Care
  • Firemin
  • Internet Friendly Media Encoder
  • Cyberfox

Learn how to quickly and easily remove the annoying notice that Firefox shows whenever you make something go fullscreen. Remove the ‘is now fullscreen’ message shown in Firefox whenever something goes full-screen.

How to disable firefox’s fullscreen warning message

Of all the Internet browsers on the market, Firefox is by far the most customisable and privacy-conscious. It’s also one of the most continuously developed and active in the wider online community, with a constant focus on what users want and need. As a result, Firefox has become a very desirable browser for those less trusting of Google and Chrome.

Firefoxes customisation allows for quite a lot of change, including the ability to remove some of the browsers less important notifications. One of which this article aims to deal with today, the ‘is now in full-screen’ message. Following the instructions shown in this guide will allow you to completely remove the annoy notification from your browser.

How Do You Remove the ‘is now fullscreen’ Message When Making Something Fullscreen on Firefox?

To begin, you’ll first need to access Firefox’s Advanced Options page ‘aka’ the about:config page. To do this open Firefox, then type about:config into the address bar and press Enter. After you have accepted the warning prompt (only appears on your first access of about:config per browser installation) use the Search bar to search:

When the entry appears, click the pencil icon (edit) to the far right of the screen. The default value will be 3000, however, changing this to 0 will completely remove the ‘is now fullscreen’ prompt. Once you’ve made the change click the Tick to save it then Restart Firefox and the message will be gone. Alternatively, you can simply reduce the amount of time it is displayed by changing the figure to a smaller amount somewhere above 0.

On a Side Note…

If you have a USB device that always shows an error like either of the following:

“The last USB device you connected to this computer malfunctioned and Windows does not recognise it”

“There might be a problem with some files on this device or disc. This can happen if you remove the device or disc before all files have been written to it. “Scan and Fix (Recommended) or “Continue without scanning”

Make sure you check out the following article which will guide you through the process for disabling USB notifications on Windows 10.

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How to disable firefox’s fullscreen warning message

how does one disable the full screen message in firefox v56.0.1

  • 1 reply
  • 9 have this problem
  • 4542 views
  • Last reply by jscher2000

How to disable firefox’s fullscreen warning message

When entering full screen mode, one is prompted with a message alerting that you have entered full screen mode. How does one disable this message.

Chosen solution

The purpose of the message is to detect when sites trigger fullscreen since that can be used to phish you with a deceptive UI. But 99.9% of the time, it’s just a video, so.

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful or accepting the risk.

(2) In the search box above the list, type or paste full and pause while the list is filtered

(3) Double-click the full-screen-api.warning.delay preference and enter 0 (that’s a zero) and click OK

(4) Double-click the full-screen-api.warning.timeout preference and enter as short a time as you like, in milliseconds, and click OK. For example, 250 is a quarter of a second.

All Replies (1)

Chosen Solution

The purpose of the message is to detect when sites trigger fullscreen since that can be used to phish you with a deceptive UI. But 99.9% of the time, it’s just a video, so.

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful or accepting the risk.

(2) In the search box above the list, type or paste full and pause while the list is filtered

Whenever I switch a video in Firefox to full screen, a message appears at the top edge of the screen, that the website is full screen now.

I find this quite annoying and unnecessary as I am the one switching to full screen. Is there a way to disable this message?

1 Answer 1

In the Firefox address bar type about:config and hit enter, then click the I accept the risk button.

Then search for full-screen-api.warning.timeout and set its value to 0 .

After this change the message is not displayed any more when switching a video to full-screen, but you still get the message when you move the cursor to the top edge of the screen.

If you want to disable the warning completely, you’d also have to change the value for full-screen-api.warning.delay to -1 . This change prevents the warning from being displayed if you move the cursor to the top screen edge.

Reminder

Please be reminded that doing this might be a security risk. Take a look at , the article provided in the comments under the question by Duncan X Simpson. This site shows how an attacker could use the full screen API to fake a website to gain access to the credentials of your online-accounts. You shouldn’t “click the link” on that site unless you’re able to figure out what’s going on behind the scene; just read.

But as the warning pops up for only three seconds by default, one could miss the warning due to looking away from the screen at that moment for some reason. For real security the warning shouldn’t time out but stay on the screen until one clicks to hide it (that would be work for the firefox team).

However, 100% security never exists and as always we have to weigh security against convenience, so if you disable the warning, keep your eyes open!