我遇到的问题是,一个元素的dragleave事件是在悬停该元素的子元素时触发的。同样,当再次悬停回父元素时,dragenter不会被触发。

我做了一个简化的小提琴:http://jsfiddle.net/pimvdb/HU6Mk/1/。

HTML:

<div id="drag" draggable="true">drag me</div>

<hr>

<div id="drop">
    drop here
    <p>child</p>
    parent
</div>

使用以下JavaScript:

$('#drop').bind({
                 dragenter: function() {
                     $(this).addClass('red');
                 },

                 dragleave: function() {
                     $(this).removeClass('red');
                 }
                });

$('#drag').bind({
                 dragstart: function(e) {
                     e.allowedEffect = "copy";
                     e.setData("text/plain", "test");
                 }
                });

它应该做的是,当拖拽一些东西时,通过将drop div设置为红色来通知用户。这是可行的,但是如果你拖动到p子元素中,拖动键就会触发,div就不再是红色了。移动回下拉div也不会使它再次变红。有必要完全移出拖放div,并再次拖回它,使其变为红色。

是否有可能阻止dragleave在拖动到子元素时发射?

2017年更新:TL;DR,查找CSS指针事件:无;如@ h.d.所述。在现代浏览器和IE11中都能运行。


当前回答

   private onDragLeave(e) {
     e.preventDefault();
     e.stopPropagation();

    if (this.isEventFromChild(e)) {
      return;
    }

    this.isDragOver = false;
  }
  
  private isEventFromChild(e): boolean {
    //relatedTarget is null on Safari, so we take it from coordinates
    const relatedTarget = e.relatedTarget || document.elementFromPoint(e.clientX, e.clientY);
    return e.currentTarget.contains(relatedTarget);
  }

其他回答

pimvdb…

你为什么不试试用滴胶代替拖胶呢?这对我很管用。希望这能解决你的问题。

请查看jsFiddle: http://jsfiddle.net/HU6Mk/118/

$('#drop').bind({
                 dragenter: function() {
                     $(this).addClass('red');
                 },

                 drop: function() {
                     $(this).removeClass('red');
                 }
                });

$('#drag').bind({
                 dragstart: function(e) {
                     e.allowedEffect = "copy";
                     e.setData("text/plain", "test");
                 }
                });

另一种工作解决方案,稍微简单一点。

//Note: Due to a bug with Chrome the 'dragleave' event is fired when hovering the dropzone, then
//      we must check the mouse coordinates to be sure that the event was fired only when 
//      leaving the window.
//Facts:
//  - [Firefox/IE] e.originalEvent.clientX < 0 when the mouse is outside the window
//  - [Firefox/IE] e.originalEvent.clientY < 0 when the mouse is outside the window
//  - [Chrome/Opera] e.originalEvent.clientX == 0 when the mouse is outside the window
//  - [Chrome/Opera] e.originalEvent.clientY == 0 when the mouse is outside the window
//  - [Opera(12.14)] e.originalEvent.clientX and e.originalEvent.clientY never get
//                   zeroed if the mouse leaves the windows too quickly.
if (e.originalEvent.clientX <= 0 || e.originalEvent.clientY <= 0) {

一个简单的解决方案是向子组件添加css规则pointer-events: none,以防止触发ondragleave。看到的例子:

function enter(event) { document.querySelector('div').style.border = '1px dashed blue'; } function leave(event) { document.querySelector('div').style.border = ''; } div { border: 1px dashed silver; padding: 16px; margin: 8px; } article { border: 1px solid silver; padding: 8px; margin: 8px; } p { pointer-events: none; background: whitesmoke; } <article draggable="true">drag me</article> <div ondragenter="enter(event)" ondragleave="leave(event)"> drop here <p>child not triggering dragleave</p> </div>

我有一个类似的问题-我的代码隐藏dropzone dragleave事件的身体被触发时悬停子元素使dropzone闪烁在谷歌Chrome。

我能够通过调度隐藏dropzone的函数来解决这个问题,而不是立即调用它。然后,如果触发另一个拖拽或拖拽,则取消预定的函数调用。

body.addEventListener('dragover', function() {
    clearTimeout(body_dragleave_timeout);
    show_dropzone();
}, false);

body.addEventListener('dragleave', function() {
    clearTimeout(body_dragleave_timeout);
    body_dragleave_timeout = setTimeout(show_upload_form, 100);
}, false);

dropzone.addEventListener('dragover', function(event) {
    event.preventDefault();
    dropzone.addClass("hover");
}, false);

dropzone.addEventListener('dragleave', function(event) {
    dropzone.removeClass("hover");
}, false);
   private onDragLeave(e) {
     e.preventDefault();
     e.stopPropagation();

    if (this.isEventFromChild(e)) {
      return;
    }

    this.isDragOver = false;
  }
  
  private isEventFromChild(e): boolean {
    //relatedTarget is null on Safari, so we take it from coordinates
    const relatedTarget = e.relatedTarget || document.elementFromPoint(e.clientX, e.clientY);
    return e.currentTarget.contains(relatedTarget);
  }