var IE = (document.all ? true : false);
var TOP = (IE ? "pixelTop" : "top");
var NS = (document.layers ? true : false);
var NS6 = (document.getElementById ? true : false);

function ArraySearch(arSearch, arSeek)
  {
  /*
  Checks if any of the elements in arSearch is present in arSeek and returns true or false accordingly
  */

  for (i in arSearch)
    {
    if (InArray(i, arSearch))
      {
      return true;
      }
    }
  return false;
  }

function InArray(mValue, arSearch)
  {
  /*
    Checks if mValue exists in arSearch and returns true or false accordingly
  */

  for (i in arSearch)
    {
    if (mValue == arSearch[i])
      {
      return true;
      }
    }
  return false;
  }

//
//Function for checking if dateStr is a valid date (ie)
//
function isValidDate(dateStr)
  {
  // Checks for the following valid date formats:
  // MM/DD/YY   MM/DD/YYYY   MM-DD-YY   MM-DD-YYYY
  // Also separates date into month, day, and year variables


  var datePat = /^(\d{1,2})(\/|-)(\d{1,2})\2(\d{2}|\d{4})$/;

  // To require a 4 digit year entry, use this line instead:
  // var datePat = /^(\d{1,2})(\/|-)(\d{1,2})\2(\d{4})$/;
  var matchArray = dateStr.match(datePat); // is the format ok?
  if (matchArray == null)
    {
    //alert("Datumformaat is incorrect.")
    return false;
    }

  month = parseInt(matchArray[1],10); // parse date into variables
  day = parseInt(matchArray[3],10);
  year = parseInt(matchArray[4],10);

  if (month < 1 || month > 12)
    { // check month range
    //alert("Maand moet een getal zijn tussen 1 en 12.");
    return false;
    }

  if (day < 1 || day > 31)
    {
    //alert("Dag moet een getal zijn tussen 1 en 31.");
    return false;
    }

  if ((month==4 || month==6 || month==9 || month==11) && day==31)
    {
    //alert("Month "+month+" heeft geen 31 dagen!")
    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("Februari " + year + " heeft geen " + day + " dagen!");
      return false;
      }
    }
  return true;
  }