Untitled

<script>
	function getURL(){
		url="action.html";
		location.href = url + "?cbo="+document.getElementById("cbo").value;
	}
</script>

<html>
	<select id="cbo">
		<option value="a">A</option>
		<option value="b">B</option>
	</select>

	<a href="javascript:getURL();">Link</a>
</html>