javascript - 如何动态获取所选选项的值并将其存储到变量中？

Question

var temparr = [];
var arrmain = [
  ["E1", "RAM", "CHENNAI", "COMP", "P1"],
  ["E2", "RAJU", "PUNE", "ELECTRO", "P1"],
  ["E3", "JOHN", "KOLKATA", "MECH", "P2"]
  ["E4", "JOHN", "KOLKATA", "MECH", "P2"]
];
var p_id;
$(document).ready(function() {

  $('#dropdown select').on('change', function() {
    p_id = $('#dropdown select :selected').val();
  });




  for (var i = 0; i < temparr.length; i++) {
    //creates option tag
    $('<option/>', {
      value: tempArray[i],
      html: tempArray[i]
    }).appendTo('#dropdown select');

  }
});

<div id='dropdown'>
  <select style="width:200px">

  </select>
</div>

我现在有一个下拉菜单，当我更改选项时，它会从数组中获取选项，然后希望将所选选项值放入变量中。那么每当我更改选项时，如何才能将该值放入变量中

Answer 1

你就快到了。您需要迭代 arrmain 数组，而不是 temparr。

您的数组中还缺少一个逗号。

试试这个

var temparr = [];
var arrmain = [
  ["E1", "RAM", "CHENNAI", "COMP", "P1"],
  ["E2", "RAJU", "PUNE", "ELECTRO", "P1"],
  ["E3", "JOHN", "KOLKATA", "MECH", "P2"],
  ["E4", "JOHN", "KOLKATA", "MECH", "P2"]
];
var p_id;
$(document).ready(function() {

  $('#dropdown select').on('change', function() {
    p_id = $('#dropdown select :selected').val();
    alert(p_id)
  });


  for (var i = 0; i < arrmain.length; i++) {

    
    $('<option/>', {
      value: arrmain[i],
      html: arrmain[i]
    }).appendTo('#dropdown select');

  }
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id='dropdown'>
  <select style="width:200px">

  </select>
</div>