Question

以下代码是该事件的实际练习：

第三次点击后，Handler1被移除，但我认为当用户第四次点击时，应该再次添加处理程序1。但是，通过几次实验，我发现如果一个事件处理程序被＆＃34; removeEventListener＆＃34;删除，那么该侦听器就不能再被添加回来。我的问题是，是否可以在Javascript中再次向事件添加一个监听器？

＆＃13;

<!doctype html>
<html>
<body>
   <button id="btn1">Click me</button>
   <script>
      var count = 0;
      function countClick() {
         count++;
      }

      function handler1() {
         alert("Handler 1 has been triggered " + count + " times!");
      }

      function handler2() {
         alert("Handler 2 has been triggered " + count + " times!");
         if(count == 3) {
            btn1.removeEventListener("click", handler1);
         }
      }

      var btn1 = document.getElementById("btn1");
      btn1.addEventListener("click", countClick);
      btn1.addEventListener("click", handler1);
      btn1.addEventListener("click", handler2);
   </script>
</body>
</html>

＆＃13;

Answer 1

＆＃13;

var count = 0;

 function countClick() {
   count++;
 }

 function handler1() {
   alert("Handler 1 has been triggered " + count + " times!");

   
 }

 function handler2() {
   alert("Handler 2 has been triggered " + count + " times!");
   if (count == 3) {
     btn1.removeEventListener("click", handler1);
   }
   
   if (count == 4) {
     btn1.addEventListener("click", handler1);
   }
 }

 var btn1 = document.getElementById("btn1");
 btn1.addEventListener("click", countClick);
 btn1.addEventListener("click", handler1);
 btn1.addEventListener("click", handler2);

＆＃13;

<body>
  <button id="btn1">Click me</button>
</body>

＆＃13;

javascript：删除一个EventListener，然后将其添加回来

1 个答案: