我现在有一个问题:我有一个js代码，它创建了一个XML文档，一个简单的文档。 问题是，当我重新运行创建文档的函数时，它将较旧的替换为较新的。

我想要这样的东西:

<root>
     <person>
            <name>Jon</name>
            <age>18</age>

     </person>
     <person>
            <name>Paco</name>
            <age>76</age>

     </person>
     <person>
            <name>Marta</name>
            <age>42</age>

     </person>


</root>

但是我一次只能处理一个文档，我不能将新创建的xml文档“追加或推入”到第一个文档中。 本地存储总是存储最新的。 我的JS代码

userInputs来自表单标记

function addTodo(e) {
  e.preventDefault();
  const userInputHTMLCollection = document.getElementsByClassName("userAdd");
  console.log(userInputHTMLCollection);

  // EDITOR: added missing '=' below:
  const userInput = [].map.call(
    userInputHTMLCollection,
    (element) => element.value
  );
  console.log(userInput[0]);
  console.log(userInput[1]);
  console.log(userInput[2]);
  console.log(userInput[3]);

  //Creem la plantilla XML.

  txt1 = `<?xml version="1.0" encoding="UTF-8"?>`;

  txt2 = `<filmoteca>`;
  txt3 = `<peli>`;
  txt4 = `<titol>` + userInput[0] + `</titol>`;
  txt5 = `<genere>` + userInput[1] + `</genere>`;
  txt6 = `<director>` + userInput[2] + `</director>`;
  txt7 = `<any>` + userInput[3] + `</any>`;
  txt8 = `</peli>`;
  txt9 = `</filmoteca>`;
  txt = txt1 + txt2 + txt3 + txt4 + txt5 + txt6 + txt7 + txt8 + txt9;
  console.log("Text Principal" + txt);

  parser = new DOMParser();
  xmlDoc = parser.parseFromString(txt, "text/xml");
  localStorage.setItem("data", xmlDoc);
  console.log(xmlDoc);

  var xmlString = new XMLSerializer().serializeToString(xmlDoc);
  console.log(xmlString);

  // ...
}

下面的函数将在LocalStorage中创建一个XMLDocument，但是我想继续添加更多。

下面是尝试将新xml添加或推入旧xml的代码

function afegirLS() {
  const userInputHTMLCollection = document.getElementsByClassName("userAdd");

  const userInput = [].map.call(
    userInputHTMLCollection,
    (element) => element.value
  );

  var informacio = localStorage.getItem("data");

  txt2 = `<filmoteca>`;
  txt3 = `<peli>`;
  txt4 = `<titol>` + userInput[0] + `</titol>`;
  txt5 = `<genere>` + userInput[1] + `</genere>`;
  txt6 = `<director>` + userInput[2] + `</director>`;
  txt7 = `<any>` + userInput[3] + `</any>`;
  txt8 = `</peli>`;
  txt9 = `</filmoteca>`;
  txt_nou = txt1 + txt2 + txt3 + txt4 + txt5 + txt6 + txt7 + txt8 + txt9;
  console.log("Text Nou" + txt_nou);

  parser2 = new DOMParser();
  afegirXML = parser2.parseFromString(txt_nou, "text/xml");

  console.log(afegirXML);
  //var xmlString2 = new XMLSerializer().serializeToString(string_vell);
  //console.log(xmlString2);

  //txt_nou.push(xmlString);
}