function isNumeric(sText)
{
   var ValidChars = "0123456789";
   var IsNumber=true;
   var Char;

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

function ct_date(f,h,o,p,q){
	fh=h;
	fo=o;
	fp=p;
	fq=q;
	if(isValidDate(fp.value + '/' + fo.value + '/' + fq.value)){
		fh.value=fp.value + '/' + fo.value + '/' + fq.value;
	}
	else{
		fh.value="";
	}
	return;
}

function isValidDate(dateStr) {
var datePat = /^(\d{1,2})(\/|-)(\d{1,2})\2(\d{4})$/;
var matchArray = dateStr.match(datePat);
if (matchArray == null) {
return false;
}
month = matchArray[1];
day = matchArray[3];
year = matchArray[4];
if (month < 1 || month > 12) {
alert("Month must be between 1 and 12.");
return false;
}
if (day < 1 || day > 31) {
return false;
}
if ((month==4 || month==6 || month==9 || month==11) && day==31) {
return false;
}
if (month == 2) {
var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
if (day>29 || (day==29 && !isleap)) {
return false;
}
}
return true;
}