How does the drag & drop feature work & implement it in raw js?

The drag and drop mechanism in web development involves a set of events and properties provided by the HTML Drag and Drop API. Here's an overview of how it works:

Drag Start (dragstart) Event:
- This event is triggered when the user starts dragging an element that has the draggable attribute set to true.
- During this event, you set the data that you want to transfer to the drop target using e.dataTransfer.setData().
```
function dragStart(event) {
  event.dataTransfer.setData("text/plain", event.target.id);
}
```

Drag Enter (dragenter) and Drag Over (dragover) Events:

These events are triggered when a draggable element enters a valid drop target.
To allow a drop to occur, you need to prevent the default behavior of these events using event.preventDefault().

function dragEnter(event) {
  event.preventDefault();
  // Highlight the drop target or perform other visual feedback.
}

function dragOver(event) {
  event.preventDefault();
  // Ensure the drop target is a valid location for the dragged element.
}

Drag Leave (dragleave) Event:
- This event is triggered when the dragged element leaves a valid drop target.
- It's an opportunity to remove any visual feedback applied during dragenter or dragover.
```
function dragLeave(event) {
  // Remove visual feedback.
}
```

Drop (drop) Event:

This event is triggered when the user releases the mouse button to drop the element onto the target.
You can access the transferred data using event.dataTransfer.getData().
Perform any necessary actions, such as appending the dragged element to the drop target.

function drop(event) {
  event.preventDefault();
  const draggedElementId = event.dataTransfer.getData("text/plain");
  const draggedElement = document.getElementById(draggedElementId);
  // Append the dragged element to the drop target.
  event.target.appendChild(draggedElement);
}

Drag End (dragend) Event:
- This event is triggered when the drag operation is completed (either dropped or canceled).
- You can perform cleanup or additional actions during this event.
```
function dragEnd(event) {
  // Perform any cleanup or additional actions.
}
```

Remember to set the draggable attribute to true on the elements you want to make draggable. Additionally, ensure that you handle the necessary events to provide visual feedback and control the drop behavior.

Implementing a drag and drop feature in raw JavaScript involves handling various events such as dragstart, dragenter, dragover, dragleave, drop, and dragend. Here's a basic example to get you started:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <style>
    #dragElement {
      width: 100px;
      height: 100px;
      background-color: lightblue;
      margin: 10px;
      cursor: grab;
    }
    #dropZone {
      width: 200px;
      height: 200px;
      background-color: lightgreen;
      margin: 10px;
    }
  </style>
  <title>Drag and Drop Example</title>
</head>
<body>

  <div id="dragElement" draggable="true" ondragstart="dragStart(event)">Drag me</div>
  <div id="dropZone" ondragenter="dragEnter(event)" ondragover="dragOver(event)" ondragleave="dragLeave(event)" ondrop="drop(event)">Drop here</div>

  <script>
    function dragStart(e) {
      e.dataTransfer.setData("text/plain", e.target.id);
    }

    function dragEnter(e) {
      e.preventDefault();
      document.getElementById("dropZone").style.border = "2px dashed red";
    }

    function dragOver(e) {
      e.preventDefault();
    }

    function dragLeave() {
      document.getElementById("dropZone").style.border = "none";
    }

    function drop(e) {
      e.preventDefault();
      document.getElementById("dropZone").style.border = "none";
      const draggedElementId = e.dataTransfer.getData("text/plain");
      const draggedElement = document.getElementById(draggedElementId);
      const dropZone = document.getElementById("dropZone");
      dropZone.appendChild(draggedElement);
    }
  </script>
</body>
</html>

This example consists of a draggable element (dragElement) and a drop zone (dropZone). The JavaScript functions handle the necessary drag and drop events. You can customize the styles and behaviors according to your needs.