function checkRadioSelected(list) {

	for (var i = 0; i < list.length ; i++)
	{
	   if (list[i].checked) {
	   		return true;
	   	}
	}
	
	return false;

} 

function checkRequired(field) {
       var isValid = true;
       var focusField = null;
       var i = 0;
       
       if (field.type == 'text' ||
           field.type == 'textarea' ||
           field.type == 'file' ||
           field.type == 'select-one' ||
           field.type == 'radio' ||
           field.type == 'checkbox' ||
           field.type == 'password') {
           
           var value = '';
			// get field's value
			if (field.type == "select-one") {
				var si = field.selectedIndex;
				if (si >= 0) {
					value = field.options[si].value;
				}
			} else if (field.type == 'checkbox') {
			    if (field.checked) {  
			        value = field.value;  
			    } 
			} else {
				value = field.value;
			}
           
	          if (trim(value).length == 0) {
	          
	              if (i == 0) {
	                  focusField = field;
	              }
	              isValid = false;
	          }
      }

       return isValid;
   }
   
   // Trim whitespace from left and right sides of s.
   function trim(s) {
       return s.replace( /^\s*/, "" ).replace( /\s*$/, "" );
   }
   
// 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 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
}