//function check if a date is a valid date
    function validate_date(date)
    {    	
       var date_str = date

       //check if the length date is zero(0)
       //the string is empty
      if(date_str.length == 0)
               return false

      //check if the length date is 10
      //beacuse date has to be a 10 digit string
      //e.g 01/01/2004
      if(date_str.length != 10)
               return false

      //split the string into an arary
      date_array = date_str.split("/")

      //if the length of the array is not equal to 3
      //it is an invalid date
      //e.g
      //date_array[0] =01
      //date_array[1] =01
      //date_array[2] =2004
      if(date_array.length != 3)
              return false
                            

       var chk    = 0;
       var maxDay = 0;
       var mm = date_array[0]
       var dd = date_array[1]       
       var yy = date_array[2]

      // var _dd=parseInt(date_array[1]);
     //  var _mm=parseInt(date_array[0]);
      // var _yy=parseInt(date_array[2]);

       // calling function to get maximum day for this month
       maxDay = max_day(mm, yy);
       if(dd!=date_array[1] || mm!=date_array[0] || yy!=date_array[2])   { chk = 1;}
       else if((dd <= 0) || (dd > maxDay)) { chk = 1;}
       else if((mm <= 0) || (mm > 12))     { chk = 1;}
       else if((yy <= 0))                  { chk = 1;}

       //if chk == 0
       //it is an invlaid date
       if(chk == 1)
       {
            return false
       }

       return true
    }

    //function to find the maximun days a month has
    function max_day(mn, yr)
    {
      var mDay;
      if((mn == 4) || (mn == 6) || (mn == 9) || (mn == 11))
      {
        mDay = 30;
      }
      else if(mn == 2)
      {
        //calling leap year function
        mDay = isLeapYear(yr) ? 29 : 28;
      }
      else
      {
        mDay = 31;
      }

      return mDay;
    }

    // function to check leap year
    function isLeapYear(yr)
    {
      if      (yr % 4 != 0)   return false;
      else if (yr % 400 == 0) return true;
      else if (yr % 100 == 0) return false;
      else                    return true;
    }