== An example for Idris' book ==
<context source="yes">
\setupexternalfigures[location=default]
\setupinteraction[state=start]
\starttext
\startTEXpage
\goto{\externalfigure[cow.pdf]}[url(http://music.ensembleklang.com/track/narayanas-cows)]
\stopTEXpage
\stoptext
</context>