If this is a custom calculation script, try something like:
var v = getField("Datum").valueAsString;
var d = util.scand("dd. mm. yyyy", v);
d.setDate(d.getDate() + 7);
event.value = util.printd("dd. mm. yyyy", d);
If this is a custom calculation script, try something like:
var v = getField("Datum").valueAsString;
var d = util.scand("dd. mm. yyyy", v);
d.setDate(d.getDate() + 7);
event.value = util.printd("dd. mm. yyyy", d);