How to write browser plug-in? _html/css_WEB-ITnose

Let me first talk about my current knowledge background. C and C are no problem. I am doing server back-end development, so I know C and scripts.
Now I need to write a browser plug-in and seek popular science knowledge.

Reply to discussion (solution)

Google's chrome browser plug-in, written in js language. Feasibility investigation under way. . .