<html>
<head>
<script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("#type").change(function(){
alert($(this).val());
});
});
</script>
</head>
<body>
<select id="type">
<option value ="volvo">Volvo</option>
<option value ="saab">Saab</option>
<option value="opel">Opel</option>
<option value="audi">Audi</option>
</select>
</body>
</html>
<head>
<script type="text/javascript" src="/jquery/jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("#fefwe").change(function(){alert(this.value)});
});
</script>
</head>
<body>
<select id="fefwe">
<option value ="volvo">Volvo</option>
<option value ="saab">Saab</option>
<option value="opel">Opel</option>
<option value="audi">Audi</option>
</select>
</body>
</html>
<head>
<script type="text/javascript" src="/jquery/jquery.js"></script>
<script type="text/javascript">
$(function(){
$("#fefwe").change(function(){alert(this.value)});
});
</script>
</head>
<body>
<select id="fefwe">
<option >请选择</option>
<option value ="volvo">Volvo</option>
<option value ="saab">Saab</option>
<option value="opel">Opel</option>
<option value="audi">Audi</option>
</select>
</body>
</html>