/**
 * DHTML date validation script. Courtesy of SmartWebby.com (http://www.smartwebby.com/dhtml/)
 * This script found @ http://www.smartwebby.com/DHTML/date_validation.asp
 * 
 * Modified slightly by Rob Wilkerson for readability or as noted at the function level
 */
 
// Declaring valid date character, minimum year and maximum year
var dtCh	= "/";
var minYear	= 1900;
var maxYear	= 2100;

function isInteger ( str )
/*
	PURPOSE:	test whether a value is an integer
	INPUT:		the value to test
	OUTPUT:		boolean
*/
{
	var vRegex = /^[0-9]*$/;
	
	return vRegex.test ( str );
}

/* Replaced by regex-based function above
function isInteger(s)
{
	var i;
    for ( i = 0; i < s.length; i++ ) {   
        // Check that current character is number.
        var c = s.charAt ( i );
        if (((c < "0") || (c > "9"))) 
			return false;
    }
	
    // All characters are numbers.
    return true;
}
*/
 
function stripCharsInBag(s, bag){
	var i;
    var returnString = "";
    // Search through string's characters one by one.
    // If character is not in bag, append to returnString.
    for (i = 0; i < s.length; i++){   
        var c = s.charAt(i);
        if (bag.indexOf(c) == -1) returnString += c;
    }
    return returnString;
}

function daysInFebruary (year){
	// February has 29 days in any year evenly divisible by four,
    // EXCEPT for centurial years which are not also divisible by 400.
    return ( ( ( year % 4 == 0 ) && ( ( !( year % 100 == 0 ) ) || ( year % 400 == 0 ) ) ) ? 29 : 28 );
}
function DaysArray ( n ) {
	for ( var i = 1; i <= n; i++ ) {
		this[i] = 31;
		if ( i == 4 || i == 6 || i == 9 || i == 11 ) {
			this[i] = 30;
		}
		if ( i == 2 ) {
			this[i] = 29;
		}
   } 
   return this;
}

function isDate ( dtStr )
{	
	var daysInMonth	= DaysArray ( 12 );
	var pos1		= dtStr.indexOf ( dtCh );
	var pos2		= dtStr.indexOf ( dtCh, pos1 + 1 );
	var strMonth	= dtStr.substring ( 0, pos1 );
	var strDay		= dtStr.substring ( pos1 + 1, pos2 );
	var strYear		= dtStr.substring ( pos2 + 1 );
	strYr			= strYear;
	
	if ( strDay.charAt(0) == "0" && strDay.length > 1 )
		strDay = strDay.substring(1);
	
	if ( strMonth.charAt(0) == "0" && strMonth.length > 1 ) 
		strMonth = strMonth.substring(1);
		
	for ( var i = 1; i <= 3; i++ ) {
		if ( strYr.charAt(0) == "0" && strYr.length > 1 ) strYr = strYr.substring(1);
	}
	month	= parseInt ( strMonth );
	day		= parseInt ( strDay );
	year	= parseInt ( strYr );
		
	if ( pos1 == -1 || pos2 == -1 ) {
		return false;
	}	
	if ( strMonth.length < 1 || month < 1 || month > 12 ) {
		return false;
	}
	if ( strDay.length < 1 || day < 1 || day > 31 || ( month == 2 && day > daysInFebruary ( year ) ) || day > daysInMonth[month] ) {
		return false;
	}
	if ( strYear.length != 4 || year == 0 || year < minYear || year > maxYear ) {
		return false;
	}
	if ( dtStr.indexOf ( dtCh, pos2 + 1 ) != -1 || isInteger ( stripCharsInBag ( dtStr, dtCh ) ) == false ) {
		return false;
	}

	return true;
}