模板const /非const参数强制转换(Template const/non-const argument cast)

 我在你的笑脸图片中添加了属性draggable="true"和ID id="myImg" 。 
 然后，如果您将dataTransfer事件属性设置并获取到originalEvent ，它可以正常工作。 
 ;） 
 
 
 
 
 
  
$(".dropzone").on("dragover", function(ev) {
  ev.preventDefault();
});

$(".dropzone").on("drop", function(ev) {
  ev.preventDefault();
  var data = ev.originalEvent.dataTransfer.getData("text");
  ev.target.appendChild(document.getElementById(data));
});

$(".dragable").on("dragstart", function(ev) {
  ev.originalEvent.dataTransfer.setData("text", ev.target.id);
});
 
  
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="dropzone" style="width: 180px; height: 180px; padding: 10px; margin: 0px; border: 1px solid black;"></div>
<br>
<div class="dropzone" style="width: 180px; height: 180px; padding: 10px; margin: 0px; border: 1px solid black;">
  <img class="dragable" draggable="true" id="myImg" src="https://image.spreadshirtmedia.net/image-server/v1/compositions/22839312/views/1,width=300,height=300,version=1478003241/smiley-smile-men-s-t-shirt.jpg" width="180">
</div>
 
 
 
 

I added the propertie draggable="true" and an ID id="myImg" to your smiley image.
 Then, if you set and get the dataTransfer event property into the originalEvent, it works fine.
 ;)
 
 
 
 
 
  
$(".dropzone").on("dragover", function(ev) {
  ev.preventDefault();
});

$(".dropzone").on("drop", function(ev) {
  ev.preventDefault();
  var data = ev.originalEvent.dataTransfer.getData("text");
  ev.target.appendChild(document.getElementById(data));
});

$(".dragable").on("dragstart", function(ev) {
  ev.originalEvent.dataTransfer.setData("text", ev.target.id);
});
 
  
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="dropzone" style="width: 180px; height: 180px; padding: 10px; margin: 0px; border: 1px solid black;"></div>
<br>
<div class="dropzone" style="width: 180px; height: 180px; padding: 10px; margin: 0px; border: 1px solid black;">
  <img class="dragable" draggable="true" id="myImg" src="https://image.spreadshirtmedia.net/image-server/v1/compositions/22839312/views/1,width=300,height=300,version=1478003241/smiley-smile-men-s-t-shirt.jpg" width="180">
</div>