Question

我使用此代码在组合框中添加新值，我的问题是如何我会将每个附加值设置为选中吗？

<legend>Combo box</legend>
                Add to Combo: <input type="text" name="txtCombo" id="txtCombo"/>
                <input type="button" value="Add" onclick="addCombo()">
                <br/>
                Combobox: <select name="combo" multiple id="combo"></select>
            </fieldset>
        </BODY>
    </HTML>
    <script>
    function addCombo() {
        var textb = document.getElementById("txtCombo");
        var combo = document.getElementById("combo");

        var option = document.createElement("option");
        option.text = textb.value;
        option.value = textb.value;
            option.value = textb.value;

        try {
            combo.add(option, null ); //Standard 
        }catch(error) {
            combo.add(option); // IE only
        }
        textb.value = "";
    }
    </script>

Answer 1

试试这个。我已添加combo.selectedIndex = combo.options.length-1;来计算所有选项并选择最高值。你必须减少它，导致索引计数为零。

＆＃13;

<legend>Combo box</legend>
Add to Combo: <input type="text" name="txtCombo" id="txtCombo"/>
<input type="button" value="Add" onclick="addCombo()">
<br/>
Combobox: <select name="combo" multiple id="combo"></select>
</fieldset>
</BODY>
</HTML>
<script>
  function addCombo() {
    var textb = document.getElementById("txtCombo");
    var combo = document.getElementById("combo");

    var option = document.createElement("option");
    option.text = textb.value;
    option.value = textb.value;
    option.value = textb.value;

    try {
      combo.add(option, null ); //Standard 
      combo.selectedIndex = combo.options.length-1;
    }catch(error) {
      combo.add(option); // IE only
    }
    textb.value = "";
  }
</script>

＆＃13;

Answer 2

gdi32

 function addCombo() {
        var textb = document.getElementById("txtCombo");
        var combo = document.getElementById("combo");
          
        var option = document.createElement("option");
        option.text = textb.value;
        option.value = textb.value;
            option.value = textb.value;
       option.selected = true;

        try {
            combo.add(option, null ); //Standard 
        }catch(error) {
            combo.add(option); // IE only
        }
        textb.value = "";
    }

Answer 3

你需要jQuery：

option.prop("selected", true);

默认选择组合框的附加值

3 个答案: