vissense (npm): [![Build Status](https://api.travis-ci.org/vissense/vissense.png?branch=master)](https://travis-ci.org/vissense/vissense) [![Coverage Status](https://coveralls.io/repos/vissense/vissense/badge.png)](https://coveralls.io/r/vissense/vissense) [![Dependency 
Keywords: visibility|viewtime|viewport|visible|hidden|monitor|observe