It would be a lot of fun if you are able to 
auto save passwords in Firefox.
 Consider a situation: One of your friends uses your computer for 
checking his Facebook. He enters his login email and password on 
Facebook login page. After hitting on Enter, Firefox does not show him 
any password saving confirmation prompt. Instead, his email and password
 is automatically saved by Firefox! Interesting, isn’t it? Yeah, you 
guessed it right. Today, we will learn how to 
auto save passwords in Firefox without any confirmation prompt. So, let us give it a go!
Auto Save passwords in Firefox:
You have to edit core files of Firefox for auto saving passwords. 
Please note that this article is for educational purpose only. I am not 
responsible for any act done by you.
Let us get into the procedure of saving passwords in Firefox.
1. Download 
PowerArchiver
 and install it on your computer. This is used to open and edit Firefox 
files. Make sure that Firefox is not running while following the further
 procedure. Exit Firefox, if running and move to next step.
2. Go to C:\Program Files\Mozilla Firefox and look for omni.ja file.
Note: Before moving to next step, make sure you have a backup of 
omni.ja file. If you want to restore your original Firefox settings, you
 need this default omni.ja file.
3. Open this file using PowerArchiver. You will see all the files 
present inside omni.ja. Go to jsloader\resources\gre\components and 
delete nsLoginManagerPrompter.js file.
4. Go back to the root folder of omni.ja file and navigate to components
 folder. In that folder, open nsLoginManagerPrompter.js file using 
Notepad++. In Notepad++, search for _showSaveLoginNotification function.
 Now, you have to edit this function as shown in the screenshot below:
 Replace all the function contents with this:
var pwmgr = this._pwmgr;
pwmgr.addLogin(aLogin); 
Save the file and allow PowerArchiver to overwrite the file in omni.ja.
5. That’s it! Your Firefox is completely configured to auto save passwords without confirmation.
Run your Firefox and login to any online account. Firefox will save 
passsword without asking any for permission. To view saved passwords in 
Firefox, go to Tools -> Options and hit on Security tab. Then click 
on Saved Passwords button. In the prompt, click on Show Passwords and 
you will be able to see saved passwords like this: