gs.print(new GlideDateTime("2011-08-01 12:00:00").getDate());

var tt=new GlideDateTime().getDate();
gs.print(tt);

var ss=new GlideDateTime("2017-11-04 12:00:00").getDate();
gs.print(ss);

gs.print(Date());

.....................................................................................

var g = new GlideDate();
g.setValue('2015-01-01');
gs.info(g);

var gDT = new GlideDateTime(g);
gs.info(gDT);

............................................................................................................................

var gdt1 = new GlideDateTime("2016-05-15");
var gdt2 = new GlideDateTime(gs.now());
var dur = new GlideDuration();

var dur = GlideDateTime.subtract(gdt1, gdt2); //the difference between gdt1 and gdt2
var temp = dur.getDisplayValue()
gs.print(temp);

var r= parseInt(temp);
if(r==30 || r==60 || r==90)
{
gs.print("trigger");
}
else
{
gs.print("no");
}

........................................................................................................................................................

var gr = new GlideRecord('incident');
gr.get('784b900d4f4533001a0f45dba310c713');
var open= gr.opened_at;
var gdt = new GlideDateTime(open);
gdt.addDays(14);
var due_date = gdt;

gs.print("Due Date After 14 days"+due_date);

gs.print("Numaric value for Open date"+gr.opened_at.dateNumericValue());

gs.print("Open Date"+gr.opened_at);

var tempp=gr.opened_at.dateNumericValue()+ 60000;

gs.print("final numaric value"+tempp);

gr.opened_at.setDateNumericValue(tempp);

gs.print("Addding 60000 to Open date"+gr.opened_at.getValue());

..............................................................................................................................

var gdt1 = new GlideDateTime("2019-04-24");

gs.print(gdt1);

var gtime1 = new GlideTime();
gtime1.setValue("00:00:20");
gdt1.add(gtime1);

gs.print(gdt1);

............................................................................................................................................

Javascript will not able give you the result without using time function

var a = new Date('2013-11-05');
var b = new Date('2013-11-05');

if(a == b) {
console.info("a equals b");
}
else {
console.log("a NOT equals b");
}

if(a.getTime() == b.getTime()) {
console.info("a equals b");
}
else {
console.log("a NOT equals b");
}