/**
 * 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=1900;
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) {
	var myArray = new Array(0);
	for (var i = 1; i <= n; i++) {
		myArray[i] = 31
		if (i==4 || i==6 || i==9 || i==11) {myArray[i] = 30}
		if (i==2) {myArray[i] = 29}
   } 
   return myArray
}

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 (month<1 || month>12){
		alert("Please enter a valid month")
		return false
	}
	if (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
}


function isValidDate(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)
	var strErr="";
	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){
		strErr = "The date format should be : mm/dd/yyyy";
	}
	else if (month<1 || month>12){
		strErr = "Please enter a valid month";
	}
	else if (day<1 || day>31 || (month==2 && day>daysInFebruary(year)) || day > daysInMonth[month]){
		strErr = "Please enter a valid day"
	}
	else if (strYear.length != 4 || year==0 || year<minYear || year>maxYear){
		strErr = "Please enter a valid 4 digit year between "+minYear+" and "+maxYear;
	}
	else if (dtStr.indexOf(dtCh,pos2+1)!=-1 || isInteger(stripCharsInBag(dtStr, dtCh))==false){
		strErr = "Please enter a valid date";
	}
return strErr
}

function validDate(txtObj){
	if (isDate(txtObj.value)==false){
		txtObj.focus()
		return false
	}
    return true
 }



<!-- Original:  Sandeep Tamhankar (stamhankar@hotmail.com) -->
<!-- Web Site:  http://207.20.242.93 -->

<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! http://javascript.internet.com -->

<!-- Begin
function IsValidTime(timeStr) {
// Checks if time is in HH:MM:SS AM/PM format.
// The seconds and AM/PM are optional.

	var timePat = /^(\d{1,2}):(\d{2})(:(\d{2}))?(\s?(AM|am|PM|pm))?$/;

	var matchArray = timeStr.match(timePat);
	if (matchArray == null) {
		alert("Time is not in a valid format.");
		return false;
	}
	
	hour = matchArray[1];
	minute = matchArray[2];
	second = matchArray[4];
	ampm = matchArray[6];

	if (second=="") { second = null; }
	if (ampm=="") { ampm = null }

	if (hour < 0  || hour > 12) {
		alert("Hour must be between 1 and 12.");
		return false;
	}
	if (hour <= 12 && ampm == null) {
		alert("You must specify AM or PM.");
		return false;
	}
	if  (hour > 12 && ampm != null) {
		alert("You can't specify AM or PM for military time.");
		return false;
	}
	if (minute<0 || minute > 59) {
		alert ("Minute must be between 0 and 59.");
		return false;
	}
	if (second != null && (second < 0 || second > 59)) {
		alert ("Second must be between 0 and 59.");
		return false;
	}

	return true;
}
//  End -->