到目前为止一切正常,按钮被禁用,直到从下拉列表中选择值,但是我希望 ---select--- 成为下拉列表中的第一个选项,但这没有发生......任何想法至于为什么?
<asp:DropDownList ID="DropDownListSubContractors" runat="server"
AppendDataBoundItems="true" DataTextField="Company_Name" DataValueField="id"
onchange='selectChanged(this);'>
<asp:ListItem Text="---Select---" Value="0" />
<asp:ListItem Text="Option 1" Value="1" />
</asp:DropDownList>
<script type="text/javascript">
function selectChanged(e) {
document.getElementById("<%= addNewSubContractor.ClientID %>").disabled
= (e.options[e.selectedIndex].value == "0") ? "disabled" : "";
}
</script>
<asp:Button ID="addNewSubContractor" Text="Add Sub Contractor"
OnClick="UploadSubContractor" runat="server" disabled='disabled' />