Leaflet an open-source JavaScript library.. example of plug-in : atlefren, An open source jQuery-plugin to create a map that follows your text with openStreetMap.

 http://leafletjs.com/
an open-source JavaScript library for mobile-friendly interactive maps.
Leaflet is designed with simplicity, performance and usability in mind. It works efficiently across all major desktop and mobile platforms out of the box, taking advantage of HTML5 and CSS3 on modern browsers while being accessible on older ones too. It can be extended with a huge amount of plugins, has a beautiful, easy to use and well-documented API and a simple, readable source code that is a joy to contribute to.

many plug-ins:

http://leafletjs.com/plugins.html

http://atlefren.github.io/storymap/
https://github.com/atlefren/storymap

to create a map that follows your text. Annotate each paragraph and place a map alongside it. Then you can zoom/pan/add marker etc to the map as the reader reads through the text.

Will not work well on mobile (map gets removed on small screens)...