本文实例讲述了JS简单操作select和dropdownlist的方法。分享给大家供大家参考。具体实现方法如下：
一、js选中服务器控件select与dropdownlist
1. js操作服务器控件select
<select id="selectID" onchange="return showMessage()">
<option value="0">==请选择==</option>
<option value="1">是</option>
<option value="2">否</option>
</select>
<script type="text/javascript" language="javascript">
function showMessage() {
if (document.getElementById("selectID").options[document.getElementById("selectID").selectedIndex].value == 1) {
alert("你好，你选择了第 1 个");
document.getElementById("txtContractName").setAttribute("enable",false);
}
else if (document.getElementById("selectID").options[document.getElementById("selectID").selectedIndex].value == 2) {
alert("你好，你选择了第 2 个");
}
}
</script>
//js操作服务器控件dropdownlist
<asp:DropDownList ID="ddlFolder" runat="server" SkinID="ddlSkin" AutoPostBack="false" OnSelectedIndexChanged="ddlFolder_SelectedIndexChanged">
<asp:ListItem Value="0">选项0</asp:ListItem>
<asp:ListItem Value="1">选项1</asp:ListItem>
</asp:DropDownList>
<asp:DropDownList ID="ddlFolder" runat="server" SkinID="ddlSkin" AutoPostBack="false" OnSelectedIndexChanged="ddlFolder_SelectedIndexChanged">
<asp:ListItem Value="0">选项0</asp:ListItem>
<asp:ListItem Value="1">选项1</asp:ListItem>
</asp:DropDownList>
JS代码：
document.getElementById("ddlFolder").value="0";//0为你要选中的项的value
2. 根据Text值设置选中某项
var DropDownListCurrencyNew = document.getElementById("ddlFolder");
for(i = 0; i < DropDownListCurrencyNew.options.length; i++)
{
if(DropDownListCurrencyNew.options[i].text == "选项0")
{
DropDownListCurrencyNew.options[i].selected = true;
}
}
二、js读取DropDownList选中项的value和text
Value：
var selValue = document.getElementById("DropDownList1").options[document.getElementById("DropDownList1").selectedIndex].value;
Text：
var selText = document.getElementById("DropDownList1").options[document.getElementById("DropDownList1").selectedIndex].text;
希望本文所述对大家的js与.net程序设计有所帮助。