我有這個程序，允許用戶在雙擊 div 時編輯它。我試圖只讓最近雙擊的 div 有邊框。我現在正在使用 addClass 方法執行此操作，我使用此函數添加 .selceted 類：$(function () { $("div").dblclick(function (e) {     clickedTD = event.target;     $(clickedTD).find(clickedTD).last.removeClass("selected").addClass("selected");  }我試圖用這個刪除最后一個選定的 div，.find(clickedTD).last.removeClass("selected") 以便最近雙擊的 div 是唯一具有 .selected 類的 div。但這不起作用，我不確定為什么。這是我的完整代碼：var text;var selectedText;var blue = document.getElementById("blue");var blue2 = document.getElementById("blue2");var elementCounter = 0;function addElement() {   var classN = event.target.id; text = document.getElementById("input").value;  // create a new div element and give it a unique id  var newDiv = document.createElement("div");  newDiv.id = 'temp'+elementCounter;  newDiv.classList = "div";  elementCounter++  if (classN == "blue"){    newDiv.classList = "blue"      } else if (classN == "red"){        newDiv.classList = "red"      } else if (classN == "green"){        newDiv.classList = "green"      } else if (classN == "blue2"){        newDiv.classList = "blue2"      }  // and give it some content  var newContent = document.createTextNode(text);     // add the text node to the newly created div  newDiv.appendChild(newContent);    // add the newly created element and its content into the DOM  var currentDiv = document.getElementById("div1");   document.body.insertBefore(newDiv, currentDiv);   $(function() {        var currentlyDragged;     $("div").draggable({     drag: function (e) {         currentlyDragged = e.target.id         selectedText = event.target;         text = $(selectedText).html();         }    });$(function () {    $("div").dblclick(function (e) {        clickedTD = event.target;        $(clickedTD).find(clickedTD).last.removeClass("selected").addClass("selected");     }    );});  });  document.getElementById("input").value = " ";}