function DateAdd()
{
var aimDay=$('txtSubStart').value;
alert(aimDay);
var aimDayDate=new Date(Date.parse(aimDay.replace(/-/g, "/")));
$('start').innerHTML=aimDayDate.getFullYear()+"年"+(parseInt(aimDayDate.getMonth())+1)+"月"+aimDayDate.getDate()+"日";
var end=new Date(aimDayDate.getFullYear(),aimDayDate.getMonth(),aimDayDate.getDate()+7);
$('end').innerHTML=end.getFullYear()+"年"+(parseInt(end.getMonth()+1))+"月"+end.getDate()+"日";
$('day').innerHTML="7";
}
<input type="text" id="txtSubStart" size="12" onclick="WdatePicker({minDate:'%y-%M-#{%d+1}'})" onchange="DateAdd()"/>
<label class="gray"></label>
自<span class="red2" id="start">2011年*月*日零时</span>起至<span class="red2" id="end">2011年*月*日*时</span>止共<span class="red2" id="day">*</span>天
