Comparing date fields in case of leap years

Question

I want to compare two date fields.. I have gotten pretty close and it even works fine..

But problem comes when "ToDate" field is a

leap year>= "FromDate"

For eg:

from date= 29/02/1996
to date= 29/02/1996
to date= 29/02/1992
to date= 29/02/1995

the code works fine..

But if

from date= 29/03/1996
to date= 29/02/1996

the code fails...

this is my code

function isDate(value)
{
    var fromDate = document.getElementById("fromDate").value
    var toDate= document.getElementById("toDate").value
    var dateRegEx = null;
    dateRegEx = new RegExp(/^(((0[1-9]|[12]\d|3[01])\/(0[13578]|1[02])\/((19|[2-9]\d)\d{2}))|((0[1-9]|[12]\d|30)\/(0[13456789]|1[012])\/((19|[2-9]\d)\d{2}))|((0[1-9]|1\d|2[0-8])\/02\/((19|[2-9]\d)\d{2}))|(29\/02\/((1[6-9]|[2-9]\d)(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00))))$/g);

    if (dateRegEx.test(fromDate)){
    }
    else{
        alert("Invalid from date");
        return false;
    }
    dateRegEx = new RegExp(/^(((0[1-9]|[12]\d|3[01])\/(0[13578]|1[02])\/((19|[2-9]\d)\d{2}))|((0[1-9]|[12]\d|30)\/(0[13456789]|1[012])\/((19|[2-9]\d)\d{2}))|((0[1-9]|1\d|2[0-8])\/02\/((19|[2-9]\d)\d{2}))|(29\/02\/((1[6-9]|[2-9]\d)(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00))))$/g);
    if(dateRegEx.test(toDate)) {
    }
    else{
        alert("Invalid to date");
        return false;
    }
    var stDate = new Date(fromDate);
    var enDate = new Date(toDate);
    var compDate = enDate - stDate;

    if(compDate > 0)
        return true;
    else
    {
        alert("Please Enter the correct date ");
        return false;
    }
    /**/
}

how to make it work for all leap years...where would i have to make changes in the code.

Possibile duplicate: http://stackoverflow.com/questions/327429/whats-the-best-way-to-calculate-date-difference-in-javascript — Stefano Sanfilippo, May 10 '13 at 12:11

score 3 · Accepted Answer · answered May 10 '13 at 12:10

3

This is an excelent jQuery plugin to do what you want: http://momentjs.com/

answered May 10 '13 at 12:10

red_alert

1,738
14
24

While moment is a great plugin... the OP is not even using jQuery. – jbabey May 10 '13 at 12:11
momentjs is not actually a jQuery plugin, so it's appropriate here. – Codesleuth May 10 '13 at 12:15
a great plugin.. but i need to solve the leap year error in the end date field. – razor May 10 '13 at 12:15

score 1 · Answer 2 · answered May 10 '13 at 12:21

Here's a solution using moment.js:

function isDate(value)
{
    var fromDate = moment(document.getElementById("fromDate").value);
    var toDate = moment(document.getElementById("toDate").value);

    if (fromDate.isValid()) {
    }
    else {
        alert("Invalid from date");
        return false;
    }

    if(toDate.isValid()) {
    }
    else {
        alert("Invalid to date");
        return false;
    }

    if(toDate.isAfter(fromDate))
        return true;
    else
    {
        alert("Please Enter the correct date ");
        return false;
    }
}

Depending on how your dates are represented, you may have to provide the moment constructor with another parameter to indicate the format. See Validation.

Comparing date fields in case of leap years

2 Answers2