'dragleave' of parent element fires when dragging over children elements

Delving into event flow and manipulation

Both event.stopPropagation() and event.preventDefault() are influential in refining event behavior. The first prevents the event from rippling through the DOM, and the second ensures no default actions are taken, enabling your custom drag-and-drop logic to reign supreme.

Assigning pointer-events: none; to children makes them oblivious to drag events thereby eliminating extraneous dragleave triggers. Event delegation can then be used to manage these events more efficiently on parent elements without the need for manually attaching and detaching event listeners.

Here's how to implement this to include a visual change on dragenter:

parent.addEventListener('dragenter', function(e) {
  e.preventDefault(); // We're adults here, we set our own rules!
  this.classList.add('drag-over'); // Put on your fancy dress, cause we're over!
});

parent.addEventListener('dragleave', function(e) {
  if (!parent.contains(e.relatedTarget)) {
    this.classList.remove('drag-over'); // Party's over, back to the casual attire!
  }
});
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Ensuring cross-browser compatibility

In the world of the web, the essence of democracy is cross-browser compatibility. While our fundamental criterion of checking event.relatedTarget stays largely consistent, event handling can be capricious across different browsers, mandating meticulous testing.

For some browsers, identifying certain drag events can be as stubborn as a mule, hence strive for a solution that is compatible with a wide range of browsers. Cross-browser tests can expose edge cases where additional tweaks are required.

Advanced drag-and-drop UI nuances

In scenarios where refined visual feedback and precise drag-and-drop behavior are as crucial as location is in real estate, complex solutions such as a transparent overlay come into play. Fitted to the parent element, this overlay captures dragleave events exclusively for the parent while steering clear from the children's antics.

// The wizardry of creating a transparent overlay starts here
let overlay = document.createElement('div');
overlay.style.position = 'absolute';
overlay.style.top = parent.offsetTop;
overlay.style.left = parent.offsetLeft;
overlay.style.width = parent.offsetWidth;
overlay.style.height = parent.offsetHeight;
document.body.appendChild(overlay); // Voila! You've pulled a rabbit out of a hat!

// Kick the overlay out on dragleave
overlay.addEventListener('dragleave', function(e) {
  // Actual parent 'dragleave' logic is treated like royalty and handled here
  document.body.removeChild(overlay); // Your work here is done, vanish!
});
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Such methods offer a more user-friendly experience. Node of caution: seamless implementation may necessitate iterative testing and enhancements. The end game is to make drag and drop as smooth as butter on hot toast for the user.

Practical approaches to crafting ideal drag-and-drop

Clean up with jQuery

Using jQuery can cut through the clutter of event handling for drag-and-drop like a hot knife through butter. The $.fn.dndhover method provides a clean and efficient way to manage dragenter and dragleave events during a drag operation, lending to code that's as clean as a whistle.

The Sherlock Holmes approach: Implementing drag event counters

A counter for drag events increments on dragenter and decrements on dragleave. This way, you'll know when the dragging has truly exited the parent, without being fooled by the sotto voce of child elements.

Sealing variables with closures

Closures, the gift wrap of JavaScript, lets you pen down variables for both dragleave and dragover handlers, ensuring a consistent narrative across events.