var W3CDOM = (document.getElementsByTagName && document.createElement);

/*-----------------------------------------------------------------------------
 * isNumber
 *  check if the value is a number
 *-----------------------------------------------------------------------------
 */
function isNumber( s, allowNull ) 
{
  s = trimL(s);
  s = trimR(s);
  num = "";

  if( s == "" )
    return allowNull;

  // check for - sign
  if( s.charAt(0) == '-' ) {
    s = s.substr(1, s.length);
    s = trimL(s);
  }

  if( s == "" )
    return allowNull;

  /* check for $ */
  if( s.charAt(0) == '$' ) {
  s = s.substr(1, s.length);
  s = trimL(s);
  }

  if( s == "" )
    return allowNull;

  for(i=0; i<s.length; i++) {
    c = s.charAt(i);
    if( (c<'0' || c>'9') && c != '.' && c != ',') {
    return false;
    }
  else
  {
    if( c>='0' || c<='9' || c == '.' )
    num = num + c;
  }
  }

  return !isNaN( parseFloat( num ));

} /* isNumber */

/*-----------------------------------------------------------------------------
 * trimL
 *-----------------------------------------------------------------------------
 */
function trimL(s)
{
  for(i=0; i<s.length; i++) {
    if( s.charAt(i) != ' ' ) 
      break;
  }

  return s.substring(i,s.length);

} /* trimL*/

/*-----------------------------------------------------------------------------
 * trimR
 *-----------------------------------------------------------------------------
 */
function trimR(s)
{
  for(i=s.length-1; i>=0; i--) {
    if( s.charAt(i) != ' ' ) 
      break;
  }

  return s.substring(0, i+1);

} /* trimR */

/*-----------------------------------------------------------------------------
 * isEmpty
 *-----------------------------------------------------------------------------
 */
function isEmpty( s )
{
  return s == '';
}/* isEmpty */


/**
 * 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) {
	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)
{
  dtStr = trimL(trimR(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
}

function ValidateForm(){
	var dt=document.frmSample.txtDate
	if (isDate(dt.value)==false){
		dt.focus()
		return false
	}
    return true
 }

function validate() {
	validForm = true;
	firstError = null;
	errorstring = '';
	var x = document.forms[0].elements;
	for (var i=0;i<x.length;i++) {
		if (isEmpty(x[i].value) && x[i].getAttribute("required"))		  
			writeError(x[i],'This field is required');
	}
	if (!W3CDOM)
		alert(errorstring);
	if (firstError)
		firstError.focus();
	return validForm;
}


function writeError(obj,message) {
	validForm = false;
	if (obj.hasError) return;
	if (W3CDOM) {
		obj.className += ' validation';
		obj.onchange = removeError;
		var sp = document.createElement('span');
		sp.className = 'validation ';
		sp.appendChild(document.createTextNode(message));
		obj.parentNode.appendChild(sp);
		obj.hasError = sp;
	}
	else {
		errorstring += obj.name + ': ' + message + '\n';
		obj.hasError = true;
	}
	if (!firstError)
		firstError = obj;
}

function removeError()
{
	this.className = this.className.substring(0,this.className.lastIndexOf(' '));
	this.parentNode.removeChild(this.hasError);
	this.hasError = null;
	this.onchange = null;
}