HTML5 拖放 getData() 仅适用于 Chrome 中的拖放事件?

2022-01-11 00:00:00 drag-and-drop javascript html

我目前正在使用 HTML5 拖放 API 开发一个项目，以提供附加功能，包括将项目拖入和拖出浏览器.我目前遇到了特定于 Chrome 的问题(否则仅在 Firefox 中测试，可以按预期工作).

I'm currently working on a project at work using the HTML5 Drag and Drop API to provide added functionality including dragging items in and out of browsers. I am currently coming across issues which are specific to Chrome (otherwise only tested in Firefox, which works as expected).

问题是我不能使用 event.dataTransfer.getData(type) 方法在 dragstart 事件之外的任何事件中返回数据集>drop 事件.

The issue is that I cannot use the event.dataTransfer.getData(type) method to return the data set on the dragstart event in any events except the drop event.

在绑定到 dragstart 事件(确实会触发)之后，我将事件设置为这样:

I set the event like so, after binding to the dragstart event (which DOES fire):

event.dataTransfer.setData('text/plain', "some string")

然后在 drop 事件中，我可以很好的获取数据.

Then in the drop event, I can get the data fine.

event.dataTransfer.getData('text/plain')

但是，我不能对任何其他事件(例如 dragover)使用与上述相同的方法.即使我在调用 setData() 后(即在 dragstart 回调中)尝试使用上面的方法，那么它仍然会返回 undefined.

However I cannot use the same method as above on any other events (such as dragover). Even if I try and use the above method on the line after calling setData() (i.e., in the dragstart callback), then it will still return undefined.

因此，在 Chrome 中，问题在于 Chrome 中的 getData 将始终返回 undefined，除了在 drop 事件回调中.(在 Firefox 中，我可以成功获取正确的数据.)

So, in Chrome, the issue is that getData in Chrome will always return undefined, except within the drop event callback. (In Firefox, I can successfully get the correct data.)

如果你有对同一个拖动元素的dataTransfer对象的引用，那为什么要等到数据被放掉才能得到数据呢?

If you have the reference to the dataTransfer object of the same dragging element, then why should you not be able to get the data until it is dropped?

只是想知道:

  • 以前有人在使用 Chrome 时遇到过这种问题吗?
  • 有哪些解决方法?
  • 或者，这是 Chrome 需要修复的问题吗?

资源:HTML5 拖放规范.

推荐答案

WebKit 和 Chrome 对何时可以调用 getData 有很大的限制.您不能在 dragstart 或 <代码>dragover.我认为这是典型的错误.

WebKit, and hence Chrome, is quite restrictive on when you can call getData. You're not allowed to do it inside dragstart or dragover. I think this is the canonical bug.

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