When you are reading a book and you find something of great interest that you would want to read later then you can use a highlighter or marker pen to highlight that portion of text. Sometimes we use multiple highlighters of different colors to highlight text of varying importance. But when you are reading an article on a website and if you find something interesting, then you have no choice but to write it down or print the webpage and then highlight the the printed page. If you are a Firefox user, then you can use the free Permarker extension to highlight any text on any webpage. The text stays highlighted across Firefox sessions, so you can visit the same webpage again and find the important information easily.
The Permarker extension is a “no-restart” add-on for Firefox, so you can start using it as soon as it is installed, without having to restart Firefox. Once Permarker is installed, you can visit any webpage and select the text that you want to highlight. Then right-click on the selected text and select Highlight from the context-menu.
The selected text on that webpage would be highlighted immediately with a light yellow background color. You can close Firefox web browser, visit that webpage again after any number of days and you would still find the text highlighted as it was on the first day.
There are no extension options for the Permarker add-on. And the yellow color is hard coded inside the extension, so you cannot choose any other color. But you can modify the extension file loader.js and change the HTML code of the highlight color to get any color you want.
Conclusions: Although Permarker is a useful extension for people who research online journals, magazines and research sites for finding information and want to highlight the text on webpages permanently, it is very minimal and does not allow you to change the highlight color (or anything else for that matter).
You can get Permarker extension for Firefox from https://addons.mozilla.org/en-US/firefox/addon/permarker/.