Javascript Date Plus 2 Weeks (14 days)

have made a fidle for you http://jsfiddle.net/pramodpv/wfwuZ/

    Date.prototype.AddDays = function(noOfDays) {
       this.setTime(this.getTime() + (noOfDays * (1000 * 60 * 60 * 24)));
       return this;
    }

    Date.prototype.toString = function() {
       return this.getMonth() + "/" + this.getDate() + "/" +  this.getFullYear().toString().slice(2); 
    }

    $(function() {
        var currentTime = new Date();
        alert(currentTime.AddDays(14));
    });

Try this:

currentTime.setDate(currentTime.getDate()+14);

var currentTime = new Date();
currentTime.setDate(currentTime.getDate()+14);

12096e5 is a magic number which is 14 days in milliseconds.

var fortnightAway = new Date(Date.now() + 12096e5);

jsFiddle.