jquery中dom操作和事件的实例学习 下拉框应用

<div class="centent">
<select multiple="multiple" id="select1" style="width:100px;height:160px;">
<option value="1">选项1</option>
<option value="2">选项2</option>
<option value="3">选项3</option>
<option value="4">选项4</option>
<option value="5">选项5</option>
<option value="6">选项6</option>
<option value="7">选项7</option>
</select>
<div>
<span id="add" >选中添加到右边&gt;&gt;</span>
<span id="add_all" >全部添加到右边&gt;&gt;</span>
</div>
</div>
<div class="centent">
<select multiple="multiple" id="select2" style="width: 100px;height:160px;">
<option value="8">选项8</option>
</select>
</div>

<script type="text/javascript">
$(function(){
$('#add').click(function(){
var $option=$('#select1 option:selected');
$option.appendTo('#select2');
})
$('#add_all').click(function(){
var $option=$('#select1 option');
$option.appendTo('#select2');
})
$('#select1').dblclick(function(){
var $option=$('option:selected',this);
$option.appendTo('#select2');
})
})
</script>