时间控件设置开始时间不大于结束时间

<div class="form-horizontal fl">
						<div class="control-group">
							<label class="control-label">生成时间</label>
							<input type="text" size="12" readonly="readonly" name="beginDate" id="starttime" value=""  class="Wdate" onClick="WdatePicker({dateFmt:'yyyy-MM-dd',maxDate:'#F{$dp.$D(\'endtime\')}'})"/> 
							<span style="*float:left;">-</span>
							<input size="12" type="text" readonly="readonly" name="endDate" id="endtime" value="" class="Wdate" onClick="WdatePicker({dateFmt:'yyyy-MM-dd',minDate:'#F{$dp.$D(\'starttime\')}'})" />
						</div>
					</div>