Simply script on web site - choice of technology

I recently started my adventure with web technologies. I write some simply sites in html5(bootstrap3). At this time I want try to implement some script on web page. Because I don't have experience with javascript, I would like to ask You(more experienced people), what technology will by the best to implement some functionality on web page, e.g. I have some script write in python, bash or powershell and I would like to rewrite it and attach them to some html button on page.