如何在 java 脚本中提交之前从 formData 中删除值

Question

在这里，我正在准备 formData 值并将其存储到一个隐藏变量中。所以我想删除添加到res变量中的值。有什么想法吗？

我试过 formData.delete(pair[0]);...没用

function prepareOCPDepEntries(isButton){

    var formEl = document.forms.mainForm;

    var formData = new FormData(formEl);

    var res = "";

     for(var pair of formData.entries()) {

       if(pair[0].startsWith("_")){

        res = res +"|"+ pair;

        formData.delete(pair[0]);

       }

    }

    document.getElementById("depEntry").value = res;

    document.forms.mainForm.disabled = true;

}

HTML代码；

对 [0] 将是 _0.0

<select name="_0.0" id="_0.0" >

<option value="1" >Y</option>

<option value="0" selected>N</option>

<option value="2" >A</option>

<option value="3" >T1</option>

<option value="4" >T2</option>

<option value="5" >T3</option>

</select></TD>

<select name="_0.1" id="_0.2" >

<option value="1" >Y</option>

<option value="0" selected>N</option>

<option value="2" >A</option>

<option value="3" >T1</option>

<option value="4" >T2</option>

<option value="5" >T3</option>

</select></TD>

Answer 1

function prepareOCPDepEntries(formEl) {

  const formData = new FormData(formEl);

  let res = "";

  for (var pair of formData.entries()) {

    console.log(pair[0])

    if (pair[0].startsWith("_")) {

      console.log(pair[0])

      res = res + "|" + pair;

      formData.delete(pair[0]);

    }

  }

  console.log([...formData.entries()]); // Works. There's only one entry in the Iterator

  document.getElementById("depEntry").value = res;

  document.forms.mainForm.disabled = true;

}

document.querySelector("#mainForm").addEventListener("submit", function(ev) {

  ev.preventDefault();

  prepareOCPDepEntries(this);

})

<form id="mainForm">

  <input value="123" name="_0.0" type="text">

  <input value="999" name="bar" type="text">

  <button>Submit</button>

</form>

<textarea id="depEntry"></textarea>