JQuery EasyUI 日期控件如何控制日期选择区间

<tr><th>发售起始日期</th>

<td><input type="text" id="usLineTime" name="usLineTime" size="20" class='easyui-validatebox Wdate'

onFocus="WdatePicker({el:'usLineTime',dateFmt:'yyyy-MM-dd',maxDate:'#F{$dp.$D('ueLineTime')}'})"

value="<fmt:formatDate value="${product.usLineTime}" pattern ="yyyy-MM-dd" />" required="true"/></td></tr>

<tr><th>发售结束日期</th><td>

<input type="text" id="ueLineTime" name="ueLineTime" size="20" class='easyui-validatebox Wdate'

onFocus="WdatePicker({el:'ueLineTime',minDate:'#F{$dp.$D('usLineTime')}'})"

value="<fmt:formatDate value="${product.ueLineTime}" pattern ="yyyy-MM-dd" />" required="true"/>

</td></tr>