Question

为什么我的脚本不起作用。我复制了jsfiddle.com中的代码，它可以工作，但在我的浏览器中没有。原因是什么？

<!doctype html>
<html>
<head>
  <title>JavaScript test</title>
  <script>
  document.getElementById('button').onclick = duplicate;
  var i = 0;
  var original = document.getElementById('duplicater');
  function duplicate() {
      var clone = original.cloneNode(true); 
      clone.id = "duplicetor" + ++i; 
      original.parentNode.appendChild(clone);
  }
  </script>
</head>
<body>
  <button id="button" onlick="duplicate()">Click me</button>
  <div id="duplicater">
      duplicate EVERYTHING INSIDE THIS DIV
  </div>
</body>
</html>

Answer 1

问题是你的javascript函数被加载到head中，在生成元素之前调用它。添加以下代码

 window.addEventListener('load', function() {
  document.getElementById('button').onclick = duplicate;
  var i = 0;
  var original = document.getElementById('duplicater');
  function duplicate() {
      var clone = original.cloneNode(true); 
      clone.id = "duplicetor" + ++i; 
      original.parentNode.appendChild(clone);
  }
  });

<强>样本

＆＃13;

<!doctype html>
<html>
<head>
  <title>JavaScript test</title>
  <script>
  window.addEventListener('load', function() {
  document.getElementById('button').onclick = duplicate;
  var i = 0;
  var original = document.getElementById('duplicater');
  function duplicate() {
      var clone = original.cloneNode(true); 
      clone.id = "duplicetor" + ++i; 
      original.parentNode.appendChild(clone);
  }
  });
  </script>
</head>
<body>
  <button id="button" onlick="duplicate()">Click me</button>
  <div id="duplicater">
      duplicate EVERYTHING INSIDE THIS DIV
  </div>
</body>
</html>

＆＃13;

Answer 2

脚本标记必须写在页面的末尾。

<html>
<head>
  <title>JavaScript test</title>
  <script>

  </script>
</head>
<body>
  <button id="button" onlick="duplicate()">Click me</button>
  <div id="duplicater">
      duplicate EVERYTHING INSIDE THIS DIV
  </div>
  <script>
    document.getElementById('button').onclick = duplicate;
  var i = 0;
  var original = document.getElementById('duplicater');
  function duplicate() {
      var clone = original.cloneNode(true); 
      clone.id = "duplicetor" + ++i; 
      original.parentNode.appendChild(clone);
  }
  </script>
</body>
</html>

Answer 3

我可以看到你在文档中读取dom元素之前提升和设置事件监听器（document.getElementById（＆＃39; button＆＃39;）。onclick = duplicate;）。这样做会引发错误。如果您运行脚本并在您尝试操作的元素之后提升，则它似乎有用。

＆＃13;

<html>
<head>
  <title>JavaScript test</title>
  <script>

  </script>
</head>
<body>
  <button id="button" onlick="duplicate()">Click me</button>
  <div id="duplicater">
      duplicate EVERYTHING INSIDE THIS DIV
  </div>
  <script>
    document.getElementById('button').onclick = duplicate;
  var i = 0;
  var original = document.getElementById('duplicater');
  function duplicate() {
      var clone = original.cloneNode(true); 
      clone.id = "duplicetor" + ++i; 
      original.parentNode.appendChild(clone);
  }
  </script>
</body>
</html>

＆＃13;

Answer 4

在javascript函数上调用它之前，需要首先初始化该元素。所以只需在标记之前传输您的javascript。

<!doctype html>
<html>
<head>
  <title>JavaScript test</title>

</head>
<body>
  <button id="button" onlick="duplicate()">Click me</button>
  <div id="duplicater">
      duplicate EVERYTHING INSIDE THIS DIV
  </div>
  <script>
  document.getElementById('button').onclick = duplicate;
  var i = 0;
  var original = document.getElementById('duplicater');
  function duplicate() {
      var clone = original.cloneNode(true); 
      clone.id = "duplicetor" + ++i; 
      original.parentNode.appendChild(clone);
  }
  </script>
</body>
</html>

Answer 5

您需要在正文部分

中添加脚本

<!doctype html>
<html>
<head>
  <title>JavaScript test</title>
</head>
<body>
  <button id="button" onlick="duplicate()">Click me</button>
  <div id="duplicater">
      duplicate EVERYTHING INSIDE THIS DIV
  </div>
  <script type='text/javascript'>
  </script>
</body>

</html>

const vector< vector< Blob< Dtype > * > > all_ tops = net_->top_vecs();  // get "top" of all layers
Blob<Dtype>* ptop = all_tops[layer_index][0];  // pointer to top blob of layer

为什么我的剧本不起作用，我认为一切都做得很好

5 个答案: