function validateTimerForm(thisform)
{
	if (!thisform.hours.value) thisform.hours.value = '0';
	if (!thisform.minutes.value) thisform.minutes.value = '0';
	if (!thisform.seconds.value) thisform.seconds.value = '0';

	with (thisform)
	{		
		if (!validateAmount(thisform.hours.value, "hours")) return false;
		if (!validateAmount(thisform.minutes.value, "minutes")) return false;
		if (!validateAmount(thisform.seconds.value, "seconds")) return false;
		
		if (thisform.hours.value == 0 && thisform.minutes.value == 0 && thisform.seconds.value == 0)
		{
			alert("Please enter a positive value for hours, minutes or seconds.");
			return false;
		}
	}
}


function validateAmount(p,name)
{
	if (isNumeric(p)) return true;
	else 
	{
		alert("Please enter a numerical value for the " + name + ".");
		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;
      }
   }
   if (sText.length == 0) IsNumber = false;
   return IsNumber;
}