使用 Javascript if 函数显示 SweetAlert 弹出窗口

Question

如果上传当前已关闭，我想显示一个 SweetAlert 弹出窗口，这是由 li 元素设置的 class 为 "upload-off"

我如何合并一个 if Javascript 条件来显示弹出窗口，如果 "upload-on" class 如果存在 <li>[=17=，则什么也不做]

我计划稍后在页面上使用 Vue，因此最好使用 Javascript 而不是 jQuery（因为我在这里与 Vue 和 jQuery 存在潜在冲突)

<!-- There are two classes which toggle, upload-off and upload-on-->
<li class="uploadli upload-off">
    <p>Upload Off</p>
</li>

<input value="" id="myuploadbutton" type="file" name="Uploader" placeholder="Upload here">

<!-- Sweetalert Popup - Only display popup if uploads are currently disabled



function upload_check() {
swal({
    text: "Uploads are currently disabled, please apply here at http://www.example.com/apply",
    icon: "error",
    buttons: ['Apply Now'],
    dangerMode: true
    })
    .then(function(value) {
    console.log('returned value:', value);
    });
}

-->

概述：用户点击上传按钮，如果 class "upload-off" 出现在 <li> 元素上，我们会得到一个 SweetAlert 弹出窗口

这是一个类似的 SweetAlert 问题

Answer 1

所以检查元素是否存在

document.querySelector("#myuploadbutton")
  .addEventListener('click', function(evt) {
    var li = document.querySelector('li.uploadli.upload-off');
    if (li) {
      evt.preventDefault()
      swal({
        text: "Uploads are currently disabled, please apply here at http://www.example.com/apply",
        icon: "error",
        buttons: ['cancel', 'Apply Now'],
        dangerMode: true
      }).then(function(value) {
        console.log('returned value:', value);
        if (value) {
          // window.location.href = "//www.example.com/apply"
        }
      });
    }
  })

<script src="https://unpkg.com/sweetalert/dist/sweetalert.min.js"></script>
<ul>
  <li class="uploadli upload-off">
    <p>Upload Off</p>
  </li>
</ul>

<input value="" id="myuploadbutton" type="file" name="Uploader" placeholder="Upload here">

Answer 2

试试这个，在 click 事件中添加 upload-off 检查的 if 条件。

删除行 event.returnValue = true; 如果你不想在上传时做任何事情

$("input[type=file]").on('click', function(event) {
  if (document.querySelector('li.uploadli.upload-off')) {
    swal({
        text: "Uploads are currently disabled, please apply here at http://www.example.com/apply",
        icon: "error",
        buttons: ['Apply Now'],
        dangerMode: true
      })
      .then(function(value) {
        console.log('returned value:', value);
      });
    event.preventDefault();
    //do something
  } else if (document.querySelector('li.uploadli.upload-on')) {
    swal({
        text: "Uploads are currently disabled, please apply here at http://www.example.com/apply",
        icon: "error",
        buttons: ['Apply Now'],
        dangerMode: true
      })
      .then(function(value) {
        console.log('returned value:', value);
      });
    event.returnValue = true; //delete if you want to do nothing on upload-on
    //   alert("nothing is done");

  } else {
    alert("nothing");
  }

});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/sweetalert/2.1.2/sweetalert.min.js"></script>
<li class="uploadli upload-off">
  <p>Upload Off</p>
</li>

<input value="" id="myuploadbutton" type="file" name="Uploader" placeholder="Upload here">

使用 Javascript if 函数显示 SweetAlert 弹出窗口

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