In nashorn openjdk repository http://hg.openjdk.java.net/jdk9/dev/nashorn,
When I came across this FXML example https://github.com/halcat0x15a/calculator/blob/master/src/calculator/calculator.fxml, I wanted to replace Java event handling + actual calculator implementation with nashorn scripts. The "ported" FMXL+nashorn script app. uses nashorn scripts for action handlers and uses "eval" to implement calculator back-end.
Calculator App in FXML + nashorn scripts
jjs -fx fxmlrunner.js -- calc.fxml