怎么不能在客户端用Javascript赋值呀！！

Question

怎么不能在客户端用Javascript赋值呀！！
<script language="javascript"   >
function okclick()
{
document.all['Order_Num_lbl'].value='99';
alert('sdfsdf');

}

</script><asp:label id="Order_Num_lbl" runat="server" Width="192px"></asp:label>
<INPUT type="button" value="Button"  onclick ="okclick();">

Answer 1

javascript“label”好像不能赋值，用textbox吧

Answer 2

你试试这样写行不行，
document.all.Order_Num_lbl.value='99';