使用html5 draggable属性时，保留拖动A元素的外观

Question

How can i preserve appearance of the dragged A element when using 'draggable' html5 attribute. On some browsers (Safari & Chrome) when dragging anchor, dragged helper is replaced with browser native implementation of dragged element as seen on the screenshots:

When dragging DIV

When dragging A

HTML

<div class="draggable">Draggable DIV</div>
<a href="" class="draggable">Draggable A</a>

CSS

$('.draggable').attr('draggable', true);

Here is the quick JSBin i assembled to demonstrate this issue http://jsbin.com/pihayeceza/1/edit

Thanks

Answer 1

I'm able to preserve the appearance of the dragged element by using DataTransfer.setDragImage . If I add the following code to the JavaScript in your jsbin instance, it work for me on Firefox, Chrome and Safari:

$('a.draggable').on('dragstart', function (ev) {
  var dt = ev.originalEvent.dataTransfer;
  // In IE browsers, setDragImage does not exist. However, the issue we are 
  // trying to fix does not happen in these broswers. So if setDragImage is not
  // available, then just don't do anything.
  if (dt.setDragImage) 
    dt.setDragImage(ev.target, 0, 0);

});

The dataTransfer field of the event has a DataTransfer object associated with the drag operation. You have to fetch it from the original DOM Event rather than from the jQuery Event wrapper, so ev.originalEvent.dataTransfer .

For IE browsers, setDragImage is not present but the problem reported in the question does not occur in the first place so if setDragImage is absent, we just don't call it.

A bin with the updated code.

Answer 2

This problem happens because the default behavior of dragging a link with an href attribute is to create an image containing the url to be used as the drag placeholder. You can fix this by removing the href attribute, however, to get around that without having to remove the href attribute you can use mousedown/up event handlers to remove the attribute and then re-add it, leaving the anchors clickable*.

 $('.draggable').attr('draggable', true).on('mousedown', function () { if ($(this).is('a')) { $(this).data('href', this.href); $(this).removeAttr('href'); } }).on('mouseup', function () { if ($(this).is('a')) { $(this).attr('href', $(this).data('href')); } }).on('click', function () { console.log(this.href); }); 

 .draggable { margin: 10px; display: block; width: 200px; background: #fafafa; color: #333; text-decoration: none; height: 40px; border: 1px solid #eaeaea; line-height: 40px; text-align: center; cursor: move; border-radius: 20px; } 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script> <div class="draggable">Draggable DIV</div> <a href="http://www.google.com" target="_blank" class="draggable">Draggable A</a> 

*Note: stack snippets doesn't let you follow the link.

Answer 3

Wrap your anchor tags with a div and set draggable="false" on the anchor tag.

<div class="draggable">
    <a href="" draggable="false">Draggable A</a>
</div>

You will need additional styling to prevent the button/link from looking blue and underlined.

.draggable a {
  color: inherit;
  text-decoration: inherit;
}

modified your jsbin here http://jsbin.com/rebayif/edit