function checkProductForm() {
	// retrieve the form field values
	objProductForm = document.getElementById("productOptionsForm");
	
	// check to see if the user selected a size
	if (trim(objProductForm.size.value) == "default") {
		alert("Please select a shoe size.");
		objProductForm.size.value = trim(objProductForm.size.value);
		objProductForm.size.focus();
		return false;
	}
	
	// check to see if the user selected a colour
	if (trim(objProductForm.colour.value) == "default") {
		alert("Please select a shoe colour.");
		objProductForm.colour.value = trim(objProductForm.colour.value);
		objProductForm.colour.focus();
		return false;
	}
	
	// check to see if the user selected a quantity
	if (trim(objProductForm.qty.value) == "default") {
		alert("Please select the quantity you would like to purchase.");
		objProductForm.qty.value = trim(objProductForm.qty.value);
		objProductForm.qty.focus();
		return false;
	}
	
	// if the function has gotten this far, then all the fields have valid values
	return true;
}