jsp关于form表单为两个按钮设置不同action的问题

<script language="javascript">
function a() {
if (confirm("确认加入订单？")) {
form.action = "../GoodsAdd";
form.submit();
}
}
function b() {
if (confirm("确认刪除")) {
form.action = "../RealLibrearyDelete";
form.submit();
}
}

</script>

<form name="form" method="post">
<tr>
<td><%=houseInfo.getHouseid()%></td>
<td><%=houseInfo.getHousename()%></td>
<td><%=houseInfo.getHouseuserrelname()%></td>
<td><%=a%></td>
<td><input type="submit" name="AddGoods" value="加入订单"
onclick="a()"></td>
<td><input type="submit" name="Delete" value="删除" onclick="b()"></td>
</tr>
<input type="hidden" name="UserName" value="<%=name%>"> <input
type="hidden" name="HouseId" value="<%=houseInfo.getHouseid()%>">
</form>

为什么无法实现跳转啊