javascript-如何从html表的选择框中获取价值

我正在尝试从HTML表中的选择框中检索值.如何选择所选值？

到目前为止,我已经尝试过：

this.cells[14].innerHTML; 
this.cells[14].children[0].innerhtml; 
this.cells[14].children[0].innerText; 

The last one .innerText returns all the items in my select box......

var table2 = document.getElementById('table_items_program');

        for (var i2 = 1; i2 < table2.rows.length; i2++) {
            table2.rows[i2].onclick = function () {
                document.getElementById("id").value = this.cells[0].innerHTML;
                document.getElementById("select").value = this.cells[14].children[0].innerText;
            }
        }

<td><select class="selectpicker" multiple>
<?php while ($row9 = mysqli_fetch_assoc($result9)):; ?>
      <option value="<?php echo $row9['id']; ?>"><?php echo $row9['id'];?>                  
      </option> 
<?php endwhile; ?>                   
</select></td>

<input style="display: inline" id="id" name="id">
<input style="display: inline" id="select" name="select">

从HTML表中的选择框中选择的值

最佳答案

How can I select the selected value?

您可以使用HTMLSelect​Element​.selected​Index方法获得选定的索引

但是,如果我了解您的麻烦.您尝试获取所选的当前值.因此,您需要获取所选选项的值.

您可以这样做：

document.getElementById('mySelect').onchange = function() {
  let options = this && this.options;
  let selectedValues = []
  for (var i = options.length; i--;) {
    let opt = options[i];
    if (opt.selected) {
      selectedValues.push(opt.value || opt.text);
    }
  }
  console.log(selectedValues)
}

<select id="mySelect" multiple>
  <option value="a"> a </option>
  <option value="b"> b </option>
  <option value="c"> c </option>
</select>

实施到您的代码示例中

for (var i2 = 1; i2 < table2.rows.length; i2++) {
  table2.rows[i2].onclick = function() {
    document.getElementById("id").value = this.cells[0].innerHTML;

    var options = this && this.cells[14].children[0].options;
    var selectedValues = []
    for (var i = options.length; i--;) {
      var opt = options[i];
      if (opt.selected) {
        selectedValues.push(opt.value || opt.text);
      }
    }
    document.getElementById("select").value = JSON.stringify(selectedValues);
  }
}