/**

 * DHTML date validation script. Courtesy of SmartWebby.com (http://www.smartwebby.com/dhtml/)

 */

// Declaring valid date character, minimum year and maximum year

var dtCh= "/";

var minYear=2000;

var maxYear=2100;



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){

		alert("The date format should be : mm/dd/yyyy");

		return false;

	}

	if (strMonth.length<1 || month<1 || month>12){

		alert("Please enter a valid month");

		return false;

	}

	if (strDay.length<1 || day<1 || day>31 || (month==2 && day>daysInFebruary(year)) || day > daysInMonth[month]){

		alert("Please enter a valid day");

		return false;

	}

	if (strYear.length != 4 || year==0 || year<minYear || year>maxYear){

		alert("Please enter a valid 4 digit year between "+minYear+" and "+maxYear);

		return false;

	}

	if (dtStr.indexOf(dtCh,pos2+1)!=-1 || isInteger(stripCharsInBag(dtStr, dtCh))==false){

		alert("Please enter a valid date");

		return false;

	}

return true;

}