<form name="form">

<TABLE>
<TR>
<TD>现在的日期：</TD>
<TD><input type="text" name="u" value="2009-01-01"></TD>
</TR>
<TR>
<TD>要加的天数：</TD>
<TD><INPUT TYPE="text" name="entry" id="d" VALUE="" onkeyup="calculate('d')"></TD>
</TR>
<TR>
<TD>要加的周数：</TD>
<TD><INPUT TYPE="text" name="entry" id="w" VALUE="" onkeyup="calculate('w')"></TD>
</TR>
<TR>
<TD>要加的月数：</TD>
<TD><INPUT TYPE="text" name="entry" id="m" VALUE="" onkeyup="calculate('m')"></TD>
</TR>
<TR>
<TD>要加的年数：</TD>
<TD><INPUT TYPE="text" name="entry" id="y" VALUE="" onkeyup="calculate('y')"></TD>
</TR>
<TR>
<TD>结果：</TD>
<TD><input name="twice"></TD>
</TR>
<!--<TR>
<TD>要加的日期2：</TD>
<TD><input type="text" name="u" value="2009/01/01"></TD>
</TR>
<TR>
<TD>结果2：</TD>
<TD><input name="twice"></TD>
</TR>-->
</TABLE>
</form>
<script language="JavaScript">
functionDateAdd(strInterval,NumDay,dtDate){
vardtTmp=newDate(dtDate);
if(isNaN(dtTmp))dtTmp=newDate();
switch(strInterval){
case"s":
dtTmp; =newDate(Date.parse(dtTmp)+(1000*parseInt(NumDay)));
break
case"n":
dtTmp; =newDate(Date.parse(dtTmp)+(60000*parseInt(NumDay)));
break
case"h":
dtTmp; =newDate(Date.parse(dtTmp)+(3600000*parseInt(NumDay)));
break;
case"d":
dtTmp; =newDate(Date.parse(dtTmp)+(86400000*parseInt(NumDay)));
break;
case"w":
dtTmp; =newDate(Date.parse(dtTmp)+((86400000*7)*parseInt(NumDay)));
break;
case"m":
dtTmp; =newDate(dtTmp.getFullYear(),(dtTmp.getMonth())+parseInt(NumDay),dtTmp.getDate(),dtTmp.getHours(),dtTmp.getMinutes(),dtTmp.getSeconds());
break;
case"y":
//alert(dtTmp.getFullYear());
dtTmp; =newDate(dtTmp.getFullYear()+parseInt(NumDay),dtTmp.getMonth(),dtTmp.getDate(),dtTmp.getHours(),dtTmp.getMinutes(),dtTmp.getSeconds());
//alert(dtTmp);
break;
}
var mStr=new String(dtTmp.getMonth()+1);
var dStr=new String(dtTmp.getDate());
if (mStr.length==1){
mStr="0"+mStr;
}
if (dStr.length==1){
dStr="0"+dStr;
}
return dtTmp.getFullYear()+"-"+mStr+"-"+dStr;
}
</script>
<script language="JavaScript">

function calculate(type)
{
var entry = document.getElementById(type).value;//自己判断是否合法
var uValue=document.form.u.value;
uValue=uValue.replace("-","/").replace("-","/");
//alert(uValue);
document.form.twice.value = DateAdd(type,entry,uValue);
}
</script>