Integer addition/subtraction issues with the Date object

Question

I was playing around with the native Date object, and I realised that subtraction works (returns an integer representing the total number of miliseconds between the two dates),

Answer 1

the + operator is overloaded for strings, - is not. You need to use

var newVal=parseInt(new Date().getTime()) + 1000

Answer 2

You can simply convert current date into milliseconds, add your desired increment then convert it back to date time format and there you have your incremented date:

var d = new Date();
alert("Current DateTime: " + d);
var milliseconds = d.getTime();  //this will convert current date  into milliseconds.. 

//Now youw want to progress the date by 3000ms.. simply add it to the current date time..
milliseconds += 3000;

d = new Date(milliseconds); //your new incremented date

alert("After 3000ms: " + d);

See the DEMO here