JavaScript 从多个选择框中删除元素

Question

我有一个表单，其中有一个选择框和一个带有两个按钮和一个文本字段的下拉菜单。在文本字段中输入一个项目，它将添加到上面的选择框和下拉菜单中。我可以弄清楚如何从选择框中删除所选项目，但如何从下拉菜单中删除它？

工作中JS FIDDLE EXAMPLE

注意:在实际表单中，这些将位于不同的选项卡上，因此您无法同时看到它们，列表只需从一个区域填充到另一个区域即可。

CSS

#sbox {
overflow: hidden;
width: 200px;
}

HTML

        <select id="sbox" name="selectbox" size="5"></select>
    <BR>
    <button type="button" class="btn btn-default" onclick="DeleteProbs();">Delete Selected Problem</button>
      </td>
  </tr>
<tr>
  <td colspan="2" valign="top"><p>To add a problem to the list, type it in the New Problem text field and then click &quot;Add to List&quot;. To remove a problem, click it in the list, then click, &quot;Delete Selected Problem&quot;<P>
    <strong>New Problem</strong><P>
    <input type="text" id="ProbAreaFrom">
     <P>
    <button type="button" class="btn btn-default" id="ProbListBtn" onclick="ListProbs();">Add to List</button>
    </p>

    Problem being detailed:<BR>
     <select name="select" id="dbox">
     </select>

JavaScript

function ListProbs() {
var x = document.getElementById("sbox");
    var txt1 = document.getElementById("ProbAreaFrom").value;
    var option = document.createElement("option");
    option.text = txt1
    x.add(option);
     ListProbs2();       
    } 

function ListProbs2() {
var y = document.getElementById("dbox");
    var txt1 = document.getElementById("ProbAreaFrom").value;
    var option = document.createElement("option");
    option.text = txt1
    y.add(option);
    ProbAreaFrom.value="";      
}     

function DeleteProbs() {
var x = document.getElementById("sbox");
for (var i = 0; i < x.options.length; i++) {
    if (x.options[i].selected) {
        x.options[i].remove();
    }
   }
}

Answer 1

function DeleteProbs() {
    var x = document.getElementById("sbox");
    var y = document.getElementById("dbox");
    var val;
    for (var i = 0; i < x.options.length; i++) {
        if (x.options[i].selected) {
            val = x.options[i].value;
            x.options[i].remove();
        }
    }
    for (var i = 0; i < y.options.length; i++) {
        if (y.options[i].value == val) {
            y.options[i].remove();
        }
    }
}