Firefox Browser Tab Activity Tracker Add-on

The following extension tracks browser tab activity - away/back. The time you leave a browser tab (change the active browser tab) and the time you returned are stored. The total time spent on the tab (page) and the time spent away are displayed to check efficiency. The data will be reset as soon as the page is refreshed.

Create a folder named tab_change and add the following manifest.json and tab_change.js files to this folder.
Go to about:debugging in Firefox and click Load Temporary Add-on and load the manifest.json file. Then visit the webpages as you normally do. The times/durations of tab changes you make will be appended to the end of the page along with the total time spent on the particular page.

Firefox Yahoo Finance Data Add-on

The following extension adds data to the Yahoo Finance Quote Page - percentage changes for Day's and 52 Week Highs and Lows will be added. The percentage changes are of that of the current price compared to the above mentioned Lows and Highs. The page needs to be refreshed to update the data.

Create a folder named yahoo_finance_data and add the following manifest.json and yahoo_finance_data.js files to this folder.

Go to about:debugging in Firefox and click Load Temporary Add-on and load the manifest.json file. Then visit Yahoo Finance Quote for a Symbol and the additional data will be displayed as shown below.

Firefox Instagram HashTag Search Add-on

The following extension adds a menu item to the right-click menu that enable you to search for the selected text. The words in the selected text is checked against a list of stop words. Subsequently, a configurable maximum number of limit words are chosen for Instagram hashtag search.

Create a folder named search_instagram and add the following manifest.json and search_instagram.js files to this folder.

Go to about:debugging in Firefox and click Load Temporary Add-on and load the manifest.json file. Then right-click on the selected text on a webpage to do a hashtag search on Instagram.

MacOS Command Line Audio File Player (afplay)

The command afplay in MacOS lets you play audio files in command line. Simply passing the file name to the command plays the entire audio file:

afplay song.mp3

You can check the available command line options to the command by looking at the man page (man afplay) or by entering the command only without any parameters (afplay). It is possible to change the volume, play duration, quality, etc.

Suppose you want to play an audio file with specified interval, say 10 seconds:

while true; do afplay song.mp3; sleep 10; done

Suppose you want to play an audio file at Random intervals:

while true; do afplay song.mp3; sleep $RANDOM; done

Here, $RANDOM is a uniform random number generator in the range 0 to  32767.

Firefox Advanced Youtube Search Add-on - Sort Criteria

The following extension adds a menu item to the right-click menu that enables you to search for the selected text with specified sort criteria - Relevance, Upload Date, View Count, Rating.

Create a folder named search_youtube_sort and add the following manifest.json and search_youtube_sort.js files to this folder.

Go to about:debugging in Firefox and click Load Temporary Add-on and load the manifest.json file. Then right-click on the selected text on a webpage and choose the sort criteria to search in Youtube.

Firefox Youtube Search Add-on

The following extension adds a menu item to the right-click menu that enabled you to search for the selected text.

Create a folder named search_youtube and add the following manifest.json and search_youtube.js files to this folder.

Go to about:debugging in Firefox and click Load Temporary Add-on and load the manifest.json file. Then right-click on the selected text on a webpage to search in Youtube.

Amazon to eBay Firefox Automatic Link Generator Add-on/Extension

The following extension adds a link to the eBay search page on the Amazon product page for the product being viewed for comparison. Clicking on the link opens a new tab with eBay search results for the Amazon product. 

Create a folder named amazon_ebay and add the following manifest.json and amazon_ebay.js files to this folder.

Go to about:debugging in Firefox and click Load Temporary Add-on and load the manifest.json file.

Then visit a product page on Amazon (amazon.com) and there will be a link 'eBay', just below the product title, pointing to the corresponding search results in eBay (ebay.com). By making appropriate changes to the manifest.json and amazon_ebay.js files you can get this extension to work on Amazon/eBay of different countries.