jQuery/JS - How to compare two date/time stamps?

Question

I have two date/time stamps:

d1 = 2011-03-02T15:30:18-08:00 
d2 = 2011-03-02T15:36:05-08:00

I want to be above to compare the two:

Answer 1

var d1= '2011-03-02T15:30:18-08:00', d2= '2011-03-02T15:36:05-08:00'; Some browsers can convert an ISO string to a Date, with new Date or Date.parse.

A lot of browsers in use today cannot-you may need to write your own conversion.

This one seems to work, but it'll need refining. I added a shim for browsers that don't have an array.map, based on mozilla org's public code.

Date.fromISO= function(s){
    var day, tz, 
    rx=  /^(\d{4}\-\d\d\-\d\d([tT][\d:\.]*)?)([zZ]|([+\-])(\d\d):(\d\d))?$/, 
    p= rx.exec(s) || [];
    if(p[1]){
        day= p[1].split(/\D/).map(function(itm){
            return parseInt(itm, 10) || 0;
        });
        day[1]-= 1;
        day= new Date(Date.UTC.apply(Date, day));
        if(!day.getDate()) return NaN;
        if(p[5]){
            tz= parseInt(p[5], 10)*60;
            if(p[6]) tz += parseInt(p[6], 10);
            if(p[4]== "+") tz*= -1;
            if(tz) day.setUTCMinutes(day.getUTCMinutes()+ tz);
        }
        return day;
    }
    return NaN;
}
Array.prototype.map= Array.prototype.map || function(fun, scope){
    var L= this.length, A= [], i= 0;
    if(typeof fun== 'function'){
        while(i< L){
            if(i in this) A[i]= fun.call(scope, this[i], i, this);
            ++i;
        }
        return A;
    }
}
var d1= '2011-03-02T15:30:18-08:00', d2= '2011-03-02T15:36:05-08:00';
alert(Date.fromISO(d1)-Date.fromISO(d2)+' milliseconds')