What is a .js file? (Virus Removal)

What is a .js file? (Virus Removal)What is a .js file? (Virus Removal)What is a .js file? (Virus Removal)

This page aims to help users understand what is a .js file and remove any of the associated .js file viruses that may come with Javascript. 

Recently, an increasing number of users have been reporting a problem where files with a .js extension are attempting to download onto the computer through the user’s browser. Here, in this article, we will explain to you what exactly is happening and how harmful it is to your system and computer. If you have that same issue on your PC, we also have prepared a removal guide that will help you stop the the nagging download requests or any other form of intrusive pop-ups that get displayed when you are using your browser. Just make sure to read all the information provided in the article itself, since it is important to have a good understanding of what you are dealing with.

Are those .js files harmful?

There’s nothing wrong with being concerned about your PC’s safety. However, many people tend to panic at the slightest sign that there’s something not quite right with their computer, thinking it is some form of a nasty virus (like a Ransomware or a Trojan). In fact, the truth is that files with extension .js are nothing but javascript files. Javascript is a programming language used in the creation and development of websites. On their own, .js files should not be a threat to your system’s security – they are not viruses. The issue here is how they are used. As we already mentioned, javascript is used in web development. Most banners, ads and pop-ups (among many other elements), that you see online are created using this programming language. However, if javascript files are getting downloaded (or are attempting to do so) without your permission and without you actually wanting them to be downloaded, then there’s likely a virus or some form of an Adware. Still, there’s no need to worry, since most of the time this is simply a very intrusive and obstructive method of online advertising that some less reputable developers employ. Nevertheless, you will still need to ensure that the piece of software responsible for the annoying pop-ups is removed from your machine.

Ad-blocker – will it help?

Some of you might have considered simply getting an add-blocker to deal with the issue. In some cases, an ad-blocker might work, but this would only be effective if an unwanted .js file or some other unwanted form of Adware (advertising-supported software) has not already gotten onto your PC. If you an unwanted ad-generating file has already made its way inside your machine, the best way to stop the nagging pop-ups is to remove it (which we will help you do).

Always deny the download!

This should go without saying, yet we will say it anyway for the sake of clarity – it is crucial that you DO NOT agree to the download. Even if .js files are not some sort of malicious Trojan Horse or Ransomware, they are surely unwanted unless you have willingly initiated the download process. In some cases, they can even directly download onto your PC without even asking for your permission. To avoid this happening to you, in our next paragraph we will give you a couple of useful tips that would help you improve your PC’s general online security.

Stay Safe while surfing the web

Almost always the issue of having unwanted downloads to your PC stems from the user’s irresponsible and/or inattentive behavior while browsing the Internet. After all, you won’t be dealing with some form of a .js downloading Adware/Malware if you only visit reputable and reliable websites that have been verified as trustworthy. Therefore, here are several simple yet crucial guidelines that you’d need to adhere to if you are to prevent any problems with unwanted .js files in future:

  • Online awareness – As we already said above, the most important thing that you need to consider while using your browser is what sites you are visiting. If you go to obscure pages with sketchy ads on them it is highly likely that you’d land a virus/Adware that would later go on to nag you with .js downloads. It is also possible that simply by visiting such sites or interacting with their banners would result in a direct download of a javascript file.
  •  Spam – Spam is another extremely common method for spreading unwanted software. All it takes from you is to click on some shady spam link to download an unwanted .js file to some random folder on your PC and then it could take hours to pinpoint that folder and delete the intrusive piece of programming. That is why, you must always think twice before you open new e-mails or interact with hyperlinks that are send to you since there’s always the chance that they are some form of spam.
  • Get a high-quality anti-virus software – Antivirus programs do not detect .js files as threats. However, they can protect your PC from other unwanted programs that might spam your PC with unwanted javascript data. Therefore, make sure to install a good and dependable security software on your PC in order to keep it safe.


Name .js File Virus
Type Trojan
Danger Level Medium (nowhere near threats like Ransomware, but still a security risk)
Symptoms  Unwanted .js file download pop-ups appearing every now and then. Sometimes, the files might get directly downloaded onto your PC, without requiring your permission. 
Distribution Method Banners throughout shady websites, spam e-mails, Adware programs that have already been installed on your PC without your knowledge.
Detection Tool

Keep in mind, SpyHunter’s malware detection tool is free. To remove the infection, you’ll need to purchase the full version.
More information about SpyHunter and steps to uninstall.

.js File Virus Removal


What is a .js file? (Virus Removal)

Some of the steps will likely require you to exit the page. Bookmark it for later reference.

Reboot in Safe Mode (use this guide if you don’t know how to do it).

What is a .js file? (Virus Removal)

Reveal All Hidden Files and Folders.

  • Do not skip this  – .js File Virus may have hidden some of its files.

Hold together the Start Key and R. Type appwiz.cpl –> OK.

What is a .js file? (Virus Removal)

You are now in the Control Panel. Look for suspicious entries. Uninstall it/them.

Type msconfig in the search field and hit enter. A window will pop-up:

What is a .js file? (Virus Removal)

Startup —> Uncheck entries that have “Unknown” as Manufacturer or otherwise look suspicious.

What is a .js file? (Virus Removal)

Hold the Start Key and R –  copy + paste the following and click OK:

notepad %windir%/system32/Drivers/etc/hosts

A new file will open. If you are hacked, there will be a bunch of other IPs connected to you at the bottom. Look at the image below:

What is a .js file? (Virus Removal)

If there are suspicious IPs below “Localhost” – write to us in the comments.

Open the start menu and search for Network Connections (On Windows 10 you just write it after clicking the Windows button), press enter.

  1. Right-click on the Network Adapter you are using —> Properties —> Internet Protocol Version 4 (ICP/IP), click  Properties.
  2. The DNS line should be set to Obtain DNS server automatically. If it is not, set it yourself.
  3. Click on Advanced —> the DNS tab. Remove everything here (if there is something) —> OK.

What is a .js file? (Virus Removal)

What is a .js file? (Virus Removal)

Right click on the browser’s shortcut —> Properties.

NOTE: We are showing Google Chrome, but you can do this for Firefox and IE (or Edge).

What is a .js file? (Virus Removal)

Properties —–> Shortcut. In Target, remove everything after .exe.

What is a .js file? (Virus Removal)

What is a .js file? (Virus Removal)  Remove .js File Virus from Internet Explorer:

Open IE, click  What is a .js file? (Virus Removal) —–> Manage Add-ons.

What is a .js file? (Virus Removal)

Find the threat —> Disable. Go to What is a .js file? (Virus Removal) —–> Internet Options —> change the URL to whatever you use (if hijacked) —> Apply.

What is a .js file? (Virus Removal) Remove .js File Virus from Firefox:

Open Firefoxclick  What is a .js file? (Virus Removal)  ——-> Add-ons —-> Extensions.

What is a .js file? (Virus Removal)

Find the adware/malware —> Remove.
What is a .js file? (Virus Removal)Remove .js File Virus from Chrome:

Close Chrome. Navigate to:

 C:/Users/!!!!USER NAME!!!!/AppData/Local/Google/Chrome/User Data. There is a Folder called “Default” inside:

What is a .js file? (Virus Removal)

Rename it to Backup Default. Restart Chrome.

  • At this point the threat is gone from Chrome, but complete the entire guide or it may reappear on a system reboot.

What is a .js file? (Virus Removal)

Press CTRL + SHIFT + ESC simultaneously. Go to the Processes Tab. Try to determine which ones are dangerous. Google them or ask us in the comments.


Right click on each of the problematic processes separately and select Open File LocationEnd the process after you open the folder, then delete the directories you were sent to.

What is a .js file? (Virus Removal)

What is a .js file? (Virus Removal)

Type Regedit in the windows search field and press Enter.

Inside, press CTRL and F together and type the threat’s Name. Right click and delete any entries you find with a similar name. If they don’t show this way, go manually to these directories and delete/uninstall them:

  • HKEY_CURRENT_USER—-Software—–Random Directory. It could be any one of them – ask us if you can’t discern which ones are malicious.
    HKEY_CURRENT_USER—-Software—Microsoft—-Windows—CurrentVersion—Run– Random
    HKEY_CURRENT_USER—-Software—Microsoft—Internet Explorer—-Main—- Random

Remember to leave us a comment if you run into any trouble!


About the author


Brandon Skies

Brandon is a researcher and content creator in the fields of cyber-security and virtual privacy. Years of experience enable him to provide readers with important information and adequate solutions for the latest software and malware problems.

Leave a Comment