如何在另一个表单中得到数据
<INPUT id=starttime readOnly size=12 name=starttime style="width:90px;border-style:solid;border-width:1;padding-left:4;padding-right:4;padding-top:1;padding-bottom:1"
onClick="event.cancelBubble=true;showCalendar('inlandcalendar1',false,'starttime',null,'setCheckInDate');javascript:ChangeTotal(this.value);" >
<font color=#002d85><span class="zi12h"><a onclick=event.cancelBubble=true;
href="javascript:showCalendar('inlandcalendar1',false,'starttime',null,'setCheckInDate');onclick=ChangeTotal(this.value);"><img src="../img/button.gif" width="34" height="21" border="0" align="absmiddle" id="inlandcalendar1"
></a>
<INPUT id=DepDate readOnly size=12
name=DepDate style="width:90px;border-style:solid;border-width:1;padding-left:4;padding-right:4;padding-top:1;padding-bottom:1">
应该怎么样写javascript才能让DepDate表单里面自己得到starttime+5天的日期呢?
比如starttime值是2007-6-10 那怎么样能得到DepDate里面值自己生成是:2007-6-15