compare dates in Javascript - Urgent

**mcwlai** · 03-31-2005 06:34 AM

Hi,

I need to compare 2 dates in a FORM which entered by users using a calender picker.

Rule: To check if date2 is < date1+28 days.

Questions:
How do I add 28 days to the field date1?
How Can I compare them?

Regards

**scragar** · 03-31-2005 06:37 AM

what format are you dates in?

**Kor** · 03-31-2005 06:39 AM

take a look at the thread below, it might be a good start:
http://www.webdeveloper.com/forum/sh...ad.php?t=53461

**mcwlai** · 03-31-2005 06:45 AM

UK format - dd/mm/yyyy

**Charles** · 03-31-2005 06:45 AM

Code:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
 "http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="Content-Script-Type" content="text/javascript">
<meta name="Content-Style-Type" content="text/css">
<title>Example</title>

<script type="text/javascript">
<!--
function check (f) {
	var start = new Date (f.start.value);
	var end = new Date (f.end.value);
	
	start.setDate (start.getDate() + 28);
	if (end >= start) {alert (); return false}
	}
// -->
</script>

<style type="text/css">
<!-- 
fieldset {padding:1ex; width:10em} 
label {display:block; margin:1em 0}
input {display:block}
button {display:block; margin:auto}
-->
</style>

</head>
<body>
<form action="some-script.pl" onsubmit="return check (this)">
<fieldset>
<legend>Dates</legend>
<label>Start Date<input name="start" onchange="this.value = new Date (this.value).toDateString()" type="text"></label>
<label>End Date<input name="end" onchange="this.value = new Date (this.value).toDateString()" type="text"></label>
<button type="submit">Submit</button>
</fieldset>
</form>
</body>
</html>

**Charles** · 03-31-2005 06:48 AM

Code:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
 "http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="Content-Script-Type" content="text/javascript">
<meta name="Content-Style-Type" content="text/css">
<title>Example</title>

<script type="text/javascript">
<!--
Date.prototype.toDDMMYYYYString = function () {return isNaN (this) ? 'NaN' : [this.getDate() > 9 ? this.getDate() : '0' + this.getDate(), this.getMonth() > 8 ? this.getMonth() + 1 : '0' +  (this.getMonth() + 1), this.getFullYear()].join('/')}

Date.fromDDMMYYYY = function (s) {return (/^(\d\d?)\D(\d\d?)\D(\d{4})$/).test(s) ? new Date(RegExp.$3, RegExp.$2 - 1, RegExp.$1) : new Date (s)}

function check (f) {
	var start = Date.fromDDMMYYYY (f.start.value);
	var end = Date.fromDDMMYYYY (f.end.value);
	
	start.setDate (start.getDate() + 28);
	if (end >= start) {alert (); return false}
	}
// -->
</script>

<style type="text/css">
<!-- 
fieldset {padding:1ex; width:10em} 
label {display:block; margin:1em 0}
input {display:block}
button {display:block; margin:auto}
-->
</style>

</head>
<body>
<form action="some-script.pl" onsubmit="return check (this)">
<fieldset>
<legend>Dates</legend>
<label>Start Date<input name="start" onchange="this.value = Date.fromDDMMYYYY (this.value).toDDMMYYYYString()" type="text"></label>
<label>End Date<input name="end" onchange="this.value = Date.fromDDMMYYYY (this.value).toDDMMYYYYString()" type="text"></label>
<button type="submit">Submit</button>
</fieldset>
</form>
</body>
</html>

**scragar** · 03-31-2005 06:54 AM

you acidentaly posted twice charles.

**Kor** · 03-31-2005 07:22 AM

Nope. In the second he solved your date format dd/mm/yyyy

**Charles** · 03-31-2005 07:29 AM

Originally Posted by Kor

Nope. In the second he solved your date format dd/mm/yyyy

Actually, the second one will take most any date format.

The native Date constructor is supposed to work with multiple formats, but just which ones is not specified. Implimentation may be locale dependent. In the US dd/mm/yyyy isn't supported to make room for our mm/dd/yyyy. Try the first one in England, just for kicks, but the second one will always work with that format. If you feed it another format then it defers to the native constructor.

Try my second one with a few other formats and you'll see another feature.

**mcwlai** · 03-31-2005 08:42 AM

Thanks guy. but it doesn't work I've put in 31/03/2005 for both start and end date but when displaying it I get "Wed Aug 1 00:00:00 UTC +0100 2007" and "Tue Jul 3 00:00:00 UTC +0100 2007"

Any idea? Do I need to convert the dates before I compare them?

**Charles** · 03-31-2005 02:47 PM

It would seem that you haven't properly copied my example.

**Warren86** · 04-01-2005 03:18 PM

<HTML>
<Head>
<Script Language=JavaScript>

function calcJulian(isDate){

gregDate = new Date(isDate);
year = gregDate.getFullYear();
month = gregDate.getMonth()+1;
day = gregDate.getDate();
A = Math.floor((7*(year+Math.floor((month+9)/12)))/4);
B = day+Math.floor((275*month)/9)
isJulian = (367*year)-A+B+1721014;
return isJulian;
}

function validate(date1,date2){

tmp = date1.split("/")
xDate = tmp[1]+"/"+tmp[0]+"/"+tmp[2];
refDate = calcJulian(xDate);
tmp = date2.split("/")
xDate = tmp[1]+"/"+tmp[0]+"/"+tmp[2];
fwdDate = calcJulian(xDate);

if (fwdDate-refDate > 28 || fwdDate <= refDate)
{
alert('Date2 Must not be more than 28 days later than Date1');
document.forms.Form1.nDate2.value = "";
document.forms.Form1.nDate2.focus();
}
}

</Script>
</Head>
<Body>
<Form name='Form1'>
Date 1 (dd/mm/yyyy): <input type=text size=9 name='nDate1' ><br>
Date 2 (dd/mm/yyyy): <input type=text size=9 name='nDate2' onblur="validate(nDate1.value,nDate2.value)"><br>
Nothing: <input type=text size=9>
</Form>
</Body>
</HTML>

**bec** · 04-03-2005 11:59 PM

Hey,

I've been stuck with this date problem for a while. I have one date in the format: month,day eg for April 4th it's: April,4

and the other date is in the format: year,month,day

i cant get the year for the first date, but i want to compare the dates. I want to know if the first date is greater than or equal to the second date

PLEASE help me!!!!

Thanks

**Charles** · 04-04-2005 04:59 AM

Code:

<script type="text/javascript">
<!--
alert (new Date ('April, 4 2005') >= new Date ('2005, May, 9'))
// -->
</script>

**nusense** · 04-04-2005 07:24 AM

Originally Posted by Charles

Actually, the second one will take most any date format.

The native Date constructor is supposed to work with multiple formats, but just which ones is not specified. Implimentation may be locale dependent. In the US dd/mm/yyyy isn't supported to make room for our mm/dd/yyyy. Try the first one in England, just for kicks, but the second one will always work with that format. If you feed it another format then it defers to the native constructor.

Try my second one with a few other formats and you'll see another feature.

IT trys to make a MEANINGFUL date out of it, the exact accepted format for in put is as stated here in the www.msdn.com site http://msdn.microsoft.com/library/de...6jsobjdate.asp

JScript

Date Object
Enables basic storage and retrieval of dates and times.

dateObj = new Date()
dateObj = new Date(dateVal)
dateObj = new Date(year, month, date[, hours[, minutes[, seconds[,ms]]]])

Arguments

dateObj Required. The variable name to which the Date object is assigned.

dateVal Required. If a numeric value, dateVal represents the number of milliseconds in Universal Coordinated Time between the specified date and midnight January 1, 1970. If a string, dateVal is parsed according to the rules in the parse method. The dateVal argument can also be a VT_DATE value as returned from some ActiveX® objects.

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