如果文本框不为空，则选中复选框

Question

我试图弄清楚如何检查所有4个输入是否都已填写，然后选中联系信息复选框。如果未填写，请取消选中该复选框。

任何帮助，将不胜感激。

$(document).on('change', '#ContactName, #ContactEmail, #ContactPhone', function() {

        if ('#ContactName, #ContactEmail, #ContactPhone' === '') {

$("#contactinformation").prop("checked", false);

} else {

$("#contactinformation").prop("checked", true);

                

}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.0/jquery.min.js"></script>

<div class="row">

  <div class="col-lg-7">

    <div class="form-group">

      <label for="ContactName">Contact name:</label>

      <input type="text" class="form-control input-sm" name="ContactName" id="ContactName" size="40" maxlength="120" value="" />

    </div>

    </div>

</div>

<div class="row">

  <div class="col-lg-7">

    <div class="form-group">

      <label for="BusinessName">Business name:</label>

      <input type="text" class="form-control input-sm" name="BusinessName" id="BusinessName" size="40" maxlength="120" value="" />

    </div>

    </div>

</div>

<div class="row">

  <div class="col-lg-7">

    <div class="form-group">

      <label for="ContactEmail">Email address:</label>

      <input type="text" class="form-control input-sm" name="ContactEmail" id="ContactEmail" size="40" maxlength="80" value="" />

    </div>

    </div>

</div>

<div class="row">

  <div class="col-lg-7">

    <div class="form-group">

      <label for="ContactPhone">Phone number (business hours):</label>

      <input type="text" class="form-control input-sm" name="ContactPhone" id="ContactPhone" size="40" maxlength="50" value="" />

    </div>

    </div>

</div>

<div class="row">

  <div class="col-lg-12">

    <div class="form-group">

      <input type="checkbox" name="contactinformation" id="contactinformation" />

      Contact information

    </div>

  </div>

</div>