function checkForm() {
    var formErrors = "Please select one product before clicking on Vote.";
    var failFields = 0;
    var docRef = document.smackdown_vote;
    var radio_choice = false;

    for (counter = 0; counter < docRef.product_id.length; counter++)
    {
	if (docRef.product_id[counter].checked)
		radio_choice = true; 
    }

    if (!radio_choice)
	failFields = 1;

    if (failFields == 1) {
        alert(formErrors);
    } else {
        docRef.submit();
    }

}