function fc_PreProcess() {
	// do something here before opening the cart... maybe some form error checking?
		// if you don't want the cart to open, say for example if there were some data validation problems you
		// want your customer to fix, then return false from this function instead of true.
	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 IsEmpty(aTextField) {
   if ((aTextField.value.length==0) ||
   (aTextField.value==null)) {
      return true;
   }
   else { return false; }
	}	

	if (!IsNumeric(document.forms["foxycart-recurring"].price.value) || IsEmpty(document.forms["foxycart-recurring"].price)) {
	document.forms["foxycart-recurring"].price.style.bordercolor = 'Red'; 
	alert("Please enter a valid numeric dollar amount.");
	return false;
	} else {
	return true;
	}
	
	if (!IsNumeric(document.forms["foxycart-single"].price.value) || IsEmpty(document.forms["foxycart-single"].price)) {
	document.forms["foxycart-single"].price.style.bordercolor = 'Red'; 
	alert("Please enter a valid numeric dollar amount.");
	return false;
	} else {
	return true;
	}

};