function IsEmpty(aTextField) {
   if ((aTextField.value.length==0) ||
   (aTextField.value==null)) {
      return true;
   }
   else { return false; }
}

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 IsDate(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;
}