Price difference video games

I need you to develop some software for me. I would like this software to be developed for Windows using Javascript. Hello, I need a chrome extension for Amazon trade-in books and games. 1- Extension should compare ( trade in value-selling price= z) seller price and amazon trade in price of a book or a game in one page of Amazon search results ( usually 25 items at a time). 2- show the result "z" right under the trade in value in three different colors. Red: If the "z" is 0 ot negative Orange: if the "z" is positive and less than 5 Green: if he is bigger than 5