如何根据下拉菜单中的输入启用/禁用某个字段？

Question

下拉菜单id = payment_method

• 由收款人支付
• 通过发票收费

下拉菜单id = shipping_carrier

• 联邦快递
• 敦豪

输入字段id = shipping_number __________________

目标：

如果用户选择通过发票收费

• 禁用shipping_carrier
• 将 Fedex 设为默认值
• hide() 我的送货号码输入

别的，

• 启用shipping_carrier
• 启用发货编号输入（必填）

代码

<script>
  var logistic = function () {
    if ($( "#payment_method option:selected" ).text("Charge through invoices")) {
        $('#shipping_carrier').prop('disabled', false);

    else {
        $('#shipping_carrier').prop('disabled', 'disabled');
    }
  };
  $(logistic);
  $("#paid_by_reciever").change(logistic);



</script>

Answer 1

干得好：

 $("#payment_method").change(function() { console.log($("#payment_method option:selected").val()); if ($("#payment_method option:selected").val() == 2) { $('#shipping_carrier').prop('disabled', 'disabled'); $('#shipping_carrier').val(1); $('#shipping_number').hide(); } else { $('#shipping_carrier').prop('disabled', false); $('#shipping_number').show(); } });

 label { display: block; margin-bottom: 10px; }

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <label> Payment method: <br /> <select id="payment_method" name="payment_method"> <option value="1">paid by reciever</option> <option value="2">charge through invoices</option> </select> </label> <label> Shipping Carrier <select id="shipping_carrier" name="shipping_carrier"> <option value="1">Fedex</option> <option value="2">DHL</option> </select><br /> </label> <label> Shipping number<br /> <input type="text" name="shipping_number" id="shipping_number" value="" /> </label>