创建一个使用javascript打开默认邮件应用程序并附加文件的表单

Question

我被要求创建一个脚本，该脚本从表单和用户输入的文件中获取值。然后，它有一个提交按钮，在客户端的计算机上打开默认邮件应用程序，并使用结构化方式从表单中检索的值填充电子邮件正文。

除了获取用户上传的文件并将它们附加到默认邮件应用程序之外，我已经能够创建一个可以完成所有操作的表单。我在互联网上到处搜索，我没有运气！有人可以帮我完善这个。我已经失去了将近3个星期了！

以下是我写的完整代码，包括表格：

<script type="text/javascript">

function update_message_body() {
  var file = document.input_form.file.value;
  var awb = document.input_form.awb.value;
  var dtsnr = document.input_form.dtsnr.value;
  var incoterms = document.input_form.incoterms.value;
  var TypeOfGoods = document.input_form.ToG.value;
  var DescriptionOfGoods = document.input_form.DoG.value;
  var quantity = document.input_form.quantity.value;
  var UnitMeasure = document.input_form.um.value;
  var ValueOfGoods = document.input_form.VoG.value;
  var TotalWeight = document.input_form.tw.value;
  var ClearingAgent = document.input_form.ca.value;
  var DEtoCA = document.input_form.DEtoCA.value;
  var CDUNHRD = document.input_form.CDUNHRD.value;

  document.proxy_form.Information.value =
    "\n" + "\n" + "This email is to inform you of the details acquired from new record :" + "\n" + "\t Uploaded Attachment :" + file + "\n" + "\t AWB :" + awb + "\n" + "\t Date and time shipping notification recieved :" + dtsnr + "\n" + "\t Incoterms :" + incoterms + "\n" + "\t Types of Goods :" + TypeOfGoods + "\n" + "\t Description of Goods :" + DescriptionOfGoods + "\n" + "\t Quantity :" + quantity + "\n" + "\t Unit Measure :" + UnitMeasure + "\n" + "\t Value of Goods :" + ValueOfGoods + "\n" + "\t Total Weight :" + TotalWeight + "\n" + "\t Clearing Agent :" + ClearingAgent + "\n" + "\t DE set to Clearing Agent :" + DEtoCA + "\n" + "\t When cargo is delivered to UNHRD :" + CDUNHRD + "\n" + "\n" + "\n" + "\n" + "Sincerely,\n";

} < /script>

<style> .dotted {
  border-style: dotted;
  padding-top: 30px;
  padding-right: 30px;
  padding-bottom: 30px;
  padding-left: 30px;
}
</style>

<!DOCTYPE html>
<html>

<body>
  <form name="input_form">
    <table class="dotted">
      <tr>
        <td>Attachment:
          <input type="file" name="file" maxlength=50 allow="file_extension">
        </td>
      </tr>
      <tr>
        <td>AWB:
          <input name="awb" type="text" pattern="[0-9]{9}" required>
        </td>
      </tr>
      <tr>
        <td>Date and time shipping notification recieved:
          <input name="dtsnr" type="datetime-local" required>
        </td>
      </tr>
      <tr>
        <td>
          Incoterms:
          <select name="incoterms" required>
            <option>CIF</option>
            <option>DAP</option>
            <option>ABC</option>
            <option>DEF</option>
            <option>GHI</option>
            <option>JKL</option>
          </select>
        </td>
      </tr>
      <tr>
        <td>
          Types of Goods:
          <select name="ToG">
            <option>Biscuit</option>
            <option>Tent</option>
            <option>Car</option>
            <option>Medical Kit</option>
          </select>
        </td>
      </tr>
      <tr>
        <td>Description of Goods:
          <input type="text" placeholder="Description of Goods" required name="DoG">
        </td>
      </tr>
      <tr>
        <td>Quantity:
          <input type="text" pattern="{9}" name="quantity" required>
        </td>
      </tr>
      <tr>
        <td>
          Unit Measure:
          <select name="um" required>
            <option>EA</option>
            <option>BX</option>
            <option>Pallet</option>
            <option>20' container</option>
            <option>40' container</option>
          </select>
        </td>
      </tr>
      <tr>
        <td>Value of Goods:
          <input type="text" pattern="{9}" name="VoG" required>
        </td>
      </tr>
      <tr>
        <td>Total Weight:
          <input type="text" pattern="{9}" name="tw" required>
        </td>
      </tr>
      <tr>
        <td>Clearing Agent:
          <input type="text" name="ca" required>
        </td>
      </tr>
      <tr>
        <td>DE set to Clearing Agent:
          <input type="date" name="DEtoCA" required>
        </td>
      </tr>
      <tr>
        <td>When cargo is delivered to UNHRD:
          <input type="date" class="textbox" name="CDUNHRD" required>
        </td>
      </tr>
    </table>
  </form>
  <form name="proxy_form" method="post" enctype="text/plain" action="mailto:?subject=Inbound Form" onSubmit="return update_message_body();">

    <input type=hidden name="Information">
    <input type=submit value="send mail">

  </form>
</body>

</html>