Why do registered events disappear when an element is removed from DOM?

Question

This jQuery 1.3.2 code adds an element to the page, registers a "click" event, then removes and reattaches the element:

var button = $('<button>Click me!</button>')
  .click(function(){ alert("Hello") })
  .appendTo('body');

$('body').html('');

button.appendTo('body');

The button appears on the page as expected, but clicking on it does nothing. I would like to know why the event handlers were removed from the object.

Note: I am aware of solutions such as jQuery.live() or clone(true) or using appendTo without a removal. What I'm looking for is an explanation, not a solution or workaround.

EDIT: I suppose this could be an arbitrary and counter-intuitive design decision of the DOM. An explanation like "Because that's the way section X of specification Y wants it to be" would be fine.

Answer 1

When you remove an element from the DOM using jQuery, all data (including event handlers) held by jQuery on that element will be destroyed. This is done to avoid memory-leaks.

This isn't a feature (or bug) of the DOM API. It's just jQuery.