JavaScript date comparison fails in IE8

Question

I have a function that converts a date to YYYY-MM-DD from DD/MM/YYYY.

This works in all browsers apart from IE8, for some reason, when creating a new Date object, it is returning NaN.

Basic implementation of the code http://jsfiddle.net/bX83c/1/

var compareDate = function(value){
    var dateFragements = value.split('/');
    if (dateFragements.length == 3) {
        var currentDate = new Date();
            currentDate.setHours(0, 0, 0, 0);

        var startDate = new Date(dateFragements[2] + '-' + dateFragements[1] + '-' + dateFragements[0]);

        if (startDate >= currentDate) {
            return true;
        } else {
            return false;
        }
    }   
}
alert(compareDate('17/09/2013'));

Answer 1

Intialise your date like this. It will work in all browsers

var startDate = new Date(dateFragements[2] , dateFragements[1] , dateFragements[0]);

There are 4 ways in which Date object can be intialised using constructor

new Date() // current date and time
new Date(milliseconds) //milliseconds since 1970/01/01
new Date(dateString)
new Date(year, month, day, hours, minutes, seconds, milliseconds)

String in Date object doesn't mean it will accept all date strings. If you want to give a string as input give this. (dateFragements[2] +'/' + dateFragements[1] + '/' + dateFragements[0]);. (/ as the separator) It will be supported in all browsers

Answer 2

IE8 expects '/' as the separator in a date string, that's why your function fails. It can be simplified to:

var compareDate = function(value){
 var dateFragements = value.split('/');
 if (dateFragements.length == 3) {
  var currentDate = function(){ return (this.setHours(0),
                                        this.setMinutes(0),
                                        this.setSeconds(0),
                                        this); }.call(new Date)
     ,startDate = new Date([dateFragements[2],
                            dateFragements[1],
                            dateFragements[0]].join('/'));
  return startDate>=currentDate;
 }   
}