/////////////////////////
// validation function //
/////////////////////////

function prepareSubmit (form) {
	
	// initialize variables for error message construction
	var message = " Oops! ";
	var fields = "";
	
	// get type value
	var typeValue = form.os0.options[form.os0.selectedIndex].value;

	// get quantity value
	for (i=0;i<form.os1.length;i++) {
		if (form.os1[i].checked) {
			var quantityValue = form.os1[i].value;
		}
	} 
	
	// check for type
	if (!typeValue) {
			fields = fields + "\n " + "You forgot to choose a party pack!";
	}	
	
	// set prices and weights for party pack
	if (quantityValue == "3 Pack") {		
		switch(typeValue) {
			case "Mixed Baking Kit (Variety Pack)":
				form.weight.value = "4.25";
				break;
			case "Chocolate Chip Cookie Kit":
				form.weight.value = "3.93";
				break;
			case "Brownie Bites Kit":
				form.weight.value = "3.62";
				break;
			case "Zebra Cupcake & Frosting Kit":
				form.weight.value = "5.18";
				break;
		}
		form.amount.value = "15.99";
	}
	
	// set prices and weights for party pack
	if (quantityValue == "6 Pack") {		
		switch(typeValue) {
			case "Mixed Baking Kit (Variety Pack)":
				form.weight.value = "8.62";
				break;
			case "Chocolate Chip Cookie Kit":
				form.weight.value = "8.93";
				break;
			case "Brownie Bites Kit":
				form.weight.value = "7.37";
				break;
			case "Zebra Cupcake & Frosting Kit":
				form.weight.value = "10.31";
				break;
		}
		form.amount.value = "30.00";
	}

	// produce alert box with errors or submit data if there are no errors
	if (fields) {
		alert(message + "\n" + fields + "\n");
		return false;
	} else {
		form.submit();
	}
}