查詢：var isResizing = false,    lastDownX = 0;$(function () {    var container = $('#container'),        top = $('#top-panel'),        handle = $('#drag');    handle.on('mousedown', function (e) {        isResizing = true;        lastDownX = e.clientY;    });    $(document).on('mousemove', function (e) {        // we don't want to do anything if we aren't resizing.        if (!isResizing)             return;        var offsetRight = top.height() + (e.clientY - container.offset().top);        top.css('top', offsetRight);    }).on('mouseup', function (e) {        // stop resizing        isResizing = false;    });});腳本：var isResizing = false// eslint-disable-next-line no-unused-varsvar lastDownX = 0function resizeVerticallyInit () {  var top = document.querySelector('#topology-container')  var handle = document.querySelector('#drag')  handle.addEventListener('mousedown', function (e) {    isResizing = true    lastDownX = e.clientY  })  document.addEventListener('mousemove', function (e) {    // we don't want to do anything if we aren't resizing.    if (!isResizing) {      return    }    var offsetRight = top.height() + 20    document.querySelector('#topology-container').style.top = offsetRight  })  document.addEventListener('mouseup', function (e) {    // stop resizing    isResizing = false  })}mounted () {  ...  resizeVerticallyInit()}如您所見，我在 mounted() 生命周期方法中的 Vue.js 組件中使用了 JavaScript 函數。我試圖轉換它，但它不起作用。首先我需要說：// eslint-disable-next-line no-unused-varsvar lastDownX = 0我不知道為什么它會抱怨 lastDownX 未被使用。第二個是錯誤："[Vue warn]: Error in mounted hook: "TypeError: Cannot read property 'addEventListener' of null"它抱怨：  handle.addEventListener('mousedown', function (e) {    isResizing = true    lastDownX = e.clientY  })有人可以幫忙轉換嗎？