Question

现在我使用此代码取消选择下拉列表的选定值，但它不起作用

var Diag = document.getElementById('<%=selDiag.ClientID%>');
var diag1 = "";
var diag2 = "";
var diag3 = "";
var diag4 = "";

var options = Diag.getElementsByTagName('option');
for (var i = 0, len = options.length; i < len; i++) {
    options[i].selected == false;
}

Answer 1

'=='是比较操作，您需要使用'='

＆＃13;

var Diag = document.getElementById('tst');

var options = Diag.getElementsByTagName('option');
for (var i = 0, len = options.length; i < len; i++) {
    options[i].selected = false;
}

＆＃13;

 <select id="tst" multiple>
  <option value="volvo" selected>Volvo</option>
  <option value="saab">Saab</option>
  <option value="vw">VW</option>
  <option value="audi" selected>Audi</option>
</select>

＆＃13;

Answer 2

为您想要的项目设置值=“”或“0”作为默认选定项目.. 这是一个例子..

<select id="To_Year" class="form-control" style="color: black; height: 36px; margin: 4px; text-align: center;">
                <%Response.Write("<option value=''>To Year</option>");

                  for (Int32 cnt = 2000; cnt <= (DateTime.Now.Year) + 5; cnt++)
                  {
                      Response.Write("<option value='" + cnt + "'>" + cnt + "</option>");
                  }

                %>
            </select>

简单地在你的脚本中调用它们如下......

$("#To_Year").val("");

OR

document.getElementById('<%=To_Year.ClientID%>').val("");

我有MultipleSeletion Dropdown我想取消选择下拉列表的值，不知道如何做到这一点

2 个答案: