你如何关闭setDragImage [英] How do you turn off setDragImage

问题描述

就像它说的那样。你如何禁用拖动图像。我有一个浮动面板，拖动图像看起来很糟糕。 no-jquery please。

just as it states. how do you disable the drag image. I have a floating panel and the drag image looks very bad. no-jquery please.

推荐答案

来自 MDN ：

如果节点是HTML img 元素，HTML canvas 元素或XUL 图像元素，图像使用数据。否则， image 应该是一个可见节点，并且将从此创建拖动图像。

If the node is an HTML img element, an HTML canvas element or a XUL image element, the image data is used. Otherwise, image should be a visible node and the drag image will be created from this.

从此可以看出，关闭拖动图像应该将空（但可见）元素传递给 setDragImage 。怎么样：

From this it would follow that to "turn off" the drag image you should just pass an empty (but visibile) element to setDragImage. How about this:

// create an empty <span>
var dragImgEl = document.createElement('span');

// set its style so it'll be effectively (but not technically) invisible and
// won't change document flow
dragImgEl.setAttribute('style',
  'position: absolute; display: block; top: 0; left: 0; width: 0; height: 0;' );

// add it to the document
document.body.appendChild(dragImgEl);

// your DataTransfer code here--assume we put it in a variable called 'dt'

dt.setDragImage(dragImgEl, 0, 0);

如果空< span> 没有由于某种原因，你总是可以使用< img src =blank.png/> 其中 blank.png 是一个透明的1像素PNG。希望有所帮助！

If an empty <span> doesn't work for some reason you could always use <img src="blank.png"/> where blank.png is a transparent 1-pixel PNG. Hope that helps!

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