function isValidDate(dateStr) {
// Checks for the following valid date formats:
//   YYYY/MM/DD     YYYY-MM-DD
if (dateStr == "") return true;  //field is not mandatory
else
{
var datePat = /^(\d{4})(\/|-)(\d{2})\2(\d{2})$/;

var matchArray = dateStr.match(datePat); // is the format ok?
if (matchArray == null) {
alert("Please enter a date in the format YYYY/MM/DD.");
return false;
}
var year = matchArray[1]; // parse date into variables
var month = matchArray[3];
var day = matchArray[4];
if (month < 1 || month > 12) { // check month range
alert("Month must be between 1 and 12.");
return false;
}
if (day < 1 || day > 31) {
alert("Day must be between 1 and 31.");
return false;
}
if ((month==4 || month==6 || month==9 || month==11) && day==31) {
alert("Month "+month+" doesn't have 31 days!")
return false
}
if (month == 2) { // check for february 29th
var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
if (day>29 || (day==29 && !isleap)) {
alert("February " + year + " doesn't have " + day + " days!");
return false;
   }
}
return true;  // date is valid
}
}

function today()
{
  var now = new Date();
  var MM = now.getMonth() + 1;
  if (MM < 10) MM = "0" + MM;
  return now.getFullYear() + "/" + MM + "/" + now.getDate();
}



function highlight(currentItem)
{
var currentRow = null;
    if (currentItem.parentNode) 
    {
        currentRow = currentItem.parentNode;
    }
    else if (currentItem.parentElement)
    {
        currentRow = currentItem.parentElement;
    }
    if (currentRow)
    {
	currentRow.className = "black";
    }
}
 
function unhighlight(currentItem)
{
    var currentRow = null;
    if (currentItem.parentNode)
    {
        currentRow = currentItem.parentNode;
    }
    else if (currentItem.parentElement)
    {
        currentRow = currentItem.parentElement;
    }
    if (currentRow) {
        currentRow.className = "white";
    }
}