function updateDropdown(form_name,field_name,select_value) {
	var fieldlength = document.forms[form_name].elements[field_name].length;
	for (var i = 0; i < fieldlength; i++) {
		document.forms[form_name].elements[field_name].options[i].selected=false;
		if (document.forms[form_name].elements[field_name].options[i].value==select_value) {
			document.forms[form_name].elements[field_name].options[i].selected=true;
		}
	}
}