javascript - 复选框 : Enable button if checkbox checked

Question

在我的页面中有一个模式窗口，在模式中我有2个复选框，我希望所有选中的复选框都启用发送按钮并更改背景颜色(如果禁用bgcolor为灰色，否则bgcolor为红色)。我怎样才能做到正确？

HTML:

<form action="" method="POST" class="send-modal-data">
    <input type="text" id="send_email" name="subscribe-email" class="modal-input" placeholder="Email *" required="required">
    <div class="checkboks custom-sq vdc-cb-area">
        <input type="checkbox" id="box4" name="vdc-modal-cb" class="checked-checkbox"/>
        <label for="box4" class="checkboks-text d-flex align-center"><?php echo the_field('vdc_checkbox_txt', 'option'); ?></label>
    </div>
    <div class="checkboks custom-sq vdc-cb-area">
        <input type="checkbox" id="box7" name="vdc-modal-cb" class="checked-checkbox" />
        <label for="box7" class="checkboks-text d-flex align-center"><?php echo the_field('vdc_checkbox_text_2', 'option'); ?></label>
    </div>
    <div class="success-msg">
        <div class="msg"></div>
    </div>
    <input type="submit" name="subscribe-form" id="vdc-send-modal" class="danger-btn send-subscribe" disabled="disabled" value="<?php echo the_field('lets_get_started', 'option'); ?>"></input>
</form>

JS:

var checks = document.getElementsByName('vdc-modal-cb');
var checkBoxList = document.getElementById('vdc-cb-area');
var sendbtn = document.getElementById('vdc-send-modal');

function allTrue(nodeList) {
  for (var i = 0; i < nodeList.length; i++) {
    if (nodeList[i].checked === false) return false;
  }
  return true;
}

checkBoxList.addEventListener('click', function(event) {
  sendbtn.disabled = true;
  if (allTrue(checks)) sendbtn.disabled = false;
  console.log(123);
});

注意:我从堆栈溢出中获取了这个示例，但它对我不起作用

Answer 1

1.您应该使用getElementsByClassName来获取具有相同类的元素。

2.要将 eventListener 添加到类元素，您应该迭代这些元素。

var checks = document.getElementsByName('vdc-modal-cb');
var checkBoxList = document.getElementsByClassName('vdc-cb-area');
var sendbtn = document.getElementById('vdc-send-modal');

function allTrue(nodeList) {
  for (var i = 0; i < nodeList.length; i++) {
    if (nodeList[i].checked === false) return false;
  }
  return true;
}

for (var i = 0; i < checkBoxList.length; i++) {
  checkBoxList[i].addEventListener('click', function(event) {
    sendbtn.disabled = true;
    if (allTrue(checks)) sendbtn.disabled = false;
  });
}