function echeck(str) {

		var at="@"
		var dot="."
		var lat=str.indexOf(at)
		var lstr=str.length
		var ldot=str.indexOf(dot)
		if (str.indexOf(at)==-1){
		   alert("Invalid E-mail ID")
		   return false
		}

		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		   alert("Invalid E-mail ID")
		   return false
		}

		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		    alert("Invalid E-mail ID")
		    return false
		}

		 if (str.indexOf(at,(lat+1))!=-1){
		    alert("Invalid E-mail ID")
		    return false
		 }

		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    alert("Invalid E-mail ID")
		    return false
		 }

		 if (str.indexOf(dot,(lat+2))==-1){
		    alert("Invalid E-mail ID")
		    return false
		 }
		
		 if (str.indexOf(" ")!=-1){
		    alert("Invalid E-mail ID")
		    return false
		 }

 		 return true					
	}

function validate_email_id(field_id, mandatory, field_name){
	var field = document.getElementById(field_id);
	var value = trim(field.value);
	field.value = value;

	if (value == ""){
		if (!mandatory) {
			return true;
		}
		alert(field_name + " can not be blank.")
		field.focus();
		return false;
	}
	if (echeck(value)==false){
		field.focus();
		return false;
	}	
	return true
}
	
	
	function validate_int(field_id, min_value, max_value, field_name, mandatory) {
	var field = document.getElementById(field_id);
	var value = trim(field.value);
	field.value = value;
	var length = value.length;
	if (length == 0) {
		if (mandatory) {
			field.focus();
			alert(field_name + " can not be left blank.");
			return false;
		}
		else {
			return true;
		}
	}
	if (!___contains_only_valid_characters(value, '1234567890')) {
		field.focus();
		alert(field_name + " must be an integer.");
		return false;
	}
	var intVal = parseInt(value);
	if (intVal < min_value) {
		field.focus();
		alert(field_name + " can not be less than " + min_value + ".");
		return false;
	}
	if (intVal > max_value) {
		field.focus();
		alert(field_name + " can not be more than " + max_value + ".");
		return false;
	}
	return true;
}

function validate_double(field_id, min_value, max_value, field_name, mandatory) {
	var field = document.getElementById(field_id);
	var value = trim(field.value);
	field.value = value;
	var length = value.length;
	if (length == 0) {
		if (mandatory) {
			field.focus();
			alert(field_name + " can not be left blank.");
			return false;
		}
		else {
			return true;
		}
	}
	if (!___contains_only_valid_characters(value, '1234567890.')) {
		field.focus();
		alert(field_name + " must be an number.");
		return false;
	}
	var doubleValue = parseFloat(value);
	if (doubleValue < min_value) {
		field.focus();
		alert(field_name + " can not be less than " + min_value + ".");
		return false;
	}
	if (doubleValue > max_value) {
		field.focus();
		alert(field_name + " can not be more than " + max_value + ".");
		return false;
	}
	return true;
}

function ___contains_only_valid_characters(text, valid_characters) {
	for (var k=0; k<text.length; k++) {
		if (valid_characters.indexOf(text.charAt(k), 0) == -1) {
			return false;
		}
	}
	return true;
}

function validate_string(field_id, min_length, max_length, field_name) {
	var field = document.getElementById(field_id);
	var value = trim(field.value);
	field.value = value;
	var length = value.length;
	if (length < min_length) {
		if (min_length == 1) {
			field.focus();
			alert(field_name + " can not be blank.");
			return false;
		}
		else {
			field.focus();
			alert(field_name + " must be atleast " + min_length + " characters.");
			return false;
		}
	}
	if (length > max_length) {
		field.focus();
		alert(field_name + " can not be more than " + max_length + " characters.");
		return false;
	}
	return true;
}

function trim_field_contents_and_return_length(field_id) {
	var field = document.getElementById(field_id);
	var value = trim(field.value);
	field.value = value;
	return value.length;
}

function trim(str) {
	return __ltrim(__rtrim(str));
}

function __ltrim(str) { 
	for(var k = 0; k < str.length && __isWhitespace(str.charAt(k)); k++);
	return str.substring(k, str.length);
}

function __rtrim(str) {
	for(var j=str.length-1; j>=0 && __isWhitespace(str.charAt(j)) ; j--) ;
	return str.substring(0,j+1);
}

function __isWhitespace(charToCheck) {
	var whitespaceChars = " \t\n\r\f";
	return (whitespaceChars.indexOf(charToCheck) != -1);
}

/**
 * DHTML date validation script for dd/mm/yyyy. 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, date_field_name){
	var daysInMonth = DaysArray(12)
	var pos1=dtStr.indexOf(dtCh)
	var pos2=dtStr.indexOf(dtCh,pos1+1)
	var strDay=dtStr.substring(0,pos1)
	var strMonth=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(date_field_name + " : The date format should be : dd/mm/yyyy")
		return false
	}
	if (strMonth.length<1 || month<1 || month>12){
		alert(date_field_name + " : Please enter a valid month")
		return false
	}
	if (strDay.length<1 || day<1 || day>31 || (month==2 && day>daysInFebruary(year)) || day > daysInMonth[month]){
		alert(date_field_name + " : Please enter a valid day")
		return false
	}
	if (strYear.length != 4 || year==0 || year<minYear || year>maxYear){
		alert(date_field_name + " : 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(date_field_name + " : Please enter a valid date")
		return false
	}
return true
}

function validate_date(field_id, mandatory, date_field_name) {
	var length = trim_field_contents_and_return_length(field_id);
	var date_field = document.getElementById(field_id);
	if (length == 0) {
		if (!mandatory) {
			return true;
		}
		else {
			date_field.focus();
			alert(date_field_name + " can not be blank.")
			return false
		}
	}
	var dt=date_field; // document.frmSample.txtDate
	if (isDate(dt.value, date_field_name)==false){
		dt.focus()
		return false
	}
    return true
 }