function validate_radio(field, alerttxt) {

	myOption = -1;
	for (i=field.length-1; i > -1; i--) {
		if (field[i].checked) {
			myOption = i; 
			i = -1;
		}
	}
	if (myOption == -1) {
		alert(alerttxt);
		return false;
	}
	else {
		return true;
	}	

}

function validate_selected(field,alerttxt) {
	with (field) {
		if (value==null||value=="0"){
			alert(alerttxt);
			return false;
		}
		else {
			return true;
		}
	}
}

function validate_required(field,alerttxt) {
	with (field) {
		if (value==null||value==""){
			alert(alerttxt);
			return false;
		}
		else {
			return true;
		}
	}
}

function validate_not_value(field,fieldvalue,alerttxt) {
	with (field) {
		if (value==fieldvalue){
			alert(alerttxt);
			return false;
		}
		else {
			return true;
		}
	}
}

function validate_email(field,alerttxt) {
	with (field){
		apos=value.indexOf("@");
		dotpos=value.lastIndexOf(".");
		if (apos<1||dotpos-apos<2) {
			alert(alerttxt);
			return false;
		}
		else {
			return true;
		}
	}
}

function validate_googlelink(field,alerttxt) {
	
	with (field){
		
		if (value.indexOf(",")==-1) {
			alert("Comma is missing");
			return false;			
		}
		
		if (value.split(",").length != 2) {
			alert("Latitude or longitude is missing. Or to many commas");
			return false;
		}		
		
		if  (IsNumeric(value.split(",")[0])==false ) {
			alert("Latitude not a number");
			return false;
		}

		if  (IsNumeric(value.split(",")[1])==false ) {
			alert("Longitude not a number");
			return false;
		}
		
		return true;
	}
}

function validate_web(field, alerttxt){
	var sValidStart = "http://";
	var sText = field.value;
	
	//It's ok to leave the fild blank
	if (sText.length == 0){
		return true;		
	}
	
	if (sText.toLowerCase().substring(0,7) == sValidStart) {
		return true;
	}
	else {
		alert(alerttxt);
		return false;
	}	
	
}

function validate_numeric(field,alerttxt){
	var ValidChars = "0123456789.";
	var IsNumber=true;
	var Char;
	var sText = field.value;
 
	for (i = 0; i < sText.length && IsNumber == true; i++) { 
		Char = sText.charAt(i); 
		if (ValidChars.indexOf(Char) == -1) {
			alert(alerttxt);
         		IsNumber = false;
		}
	}
	return IsNumber;
}


function getQueryVariable(variable, strUrl) 
{ 
	
	var query = strUrl; 
	var vars = query.split("&"); 
	
	for (var i=0;i<vars.length;i++){ 
		var pair = vars[i].split("="); 
		if (pair[0] == variable){
			return pair[1]; 
		} 
	} 
	
	return "";
} 

function IsNumeric(sText)
{
   var ValidChars = "-0123456789.";
   var IsNumber=true;
   var Char;

   if (sText.length <= 0){
   	return false;
   }
 
	//HOTFIX - ONLY ONE '.'
	if (sText.split(".").length != 2) {
		return false;
	}
	
 	//HOTFIX - MAX ONE '-'
 	if (sText.split("-").length > 2) {
		return false;
	}
 
   for (i = 0; i < sText.length && IsNumber == true; i++) 
      { 
      Char = sText.charAt(i); 
      if (ValidChars.indexOf(Char) == -1) 
         {
         IsNumber = false;
         }
      }
   return IsNumber;
   
   }


function IsUKchars(sText)
{
   var ValidChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_ ";
   var IsNumber=true;
   var Char;

   if (sText.length <= 0){
   	return false;
   }
 
   for (i = 0; i < sText.length && IsNumber == true; i++) 
      { 
      Char = sText.charAt(i); 
      if (ValidChars.indexOf(Char) == -1) 
         {
         IsNumber = false;
         }
      }
   return IsNumber;
   
}




// 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){
	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 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("The date format should be : dd-mm-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
}