JavaScript Generator Web based Application like HelloBar

I am a newbies developer. I want to create a web based application, user will be able to create pop-up massage using front-end building tools. Finally user will get a JavaScript code. They can use this code on their website body. so that they can get that pop up massage on their /www.hellobar.com script sample http://ift.tt/2lCdPGY

Regards Md.Razu Ahammed