function isChecked(butts) {
    for(i=0; i<butts.length; i++) if(butts[i].checked) return true;
    return false;
} 

function check_form(theform) {
	if(!isChecked(theform.upsell)) {
		alert('Please select a colour');
		return false;
	} else {
		return true;
	}
}