Drag and Drop: Do the Drop - ondrop

function drop(ev) {
  ev.preventDefault();
  var data = ev.dataTransfer.getData("text");
  ev.target.appendChild(document.getElementById(data));
}

//Code explained:

//-Call preventDefault() to prevent the browser default handling of the data 
// (default is open as link on drop)
//-Get the dragged data with the dataTransfer.getData() method. This method
// will return any data that was set to the same type in the setData() method
//-The dragged data is the id of the dragged element ("drag1")
//-Append the dragged element into the drop element