回显select选中的值:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<select name="" class="selectD">
<option value="兰陵王">兰陵王</option>
<option value="亚瑟">亚瑟</option>
<option value="鲁班">鲁班</option>
<option value="老夫子">老夫子</option>
</select>
</body>
<script src="js/jquery-2.1.1.js" type="text/javascript" charset="utf-8"></script>
<script type="text/javascript">
var val = '鲁班'; //初始值
$(".selectD option[value='"+val+"']").attr("selected","selected");
</script>
</html>
另(获取select选中的值):
var value= $('#select option:selected').text();