Question: how to calculate date difference in servicenow?
Answer: var gdt1 = new GlideDateTime("2011-08-28 09:00:00");
var gdt2 = new GlideDateTime("2011-08-31 08:00:00");
var dur = new GlideDuration();
var dur = GlideDateTime. subtract(gdt1, gdt2); //the difference between gdt1 and gdt2.
gs. print(dur. getDisplayValue());