WordPress/wp-admin/js/categories.js

jQuery(document).ready(function($) {
	var options = false, addAfter, delBefore, delAfter;
	if ( document.forms['addcat'].category_parent )
		options = document.forms['addcat'].category_parent.options;

	addAfter = function( r, settings ) {
		var name, id;

		name = $("<span>" + $('name', r).text() + "</span>").text();
		id = $('cat', r).attr('id');
		options[options.length] = new Option(name, id);
	}

	delAfter = function( r, settings ) {
		var id = $('cat', r).attr('id'), o;
		for ( o = 0; o < options.length; o++ )
			if ( id == options[o].value )
				options[o] = null;
	}

	delBefore = function(s) {
		if ( 'undefined' != showNotice )
			return showNotice.warn() ? s : false;

		return s;
	}

	if ( options )
		$('#the-list').wpList( { addAfter: addAfter, delBefore: delBefore, delAfter: delAfter } );
	else
		$('#the-list').wpList({ delBefore: delBefore });

	$('.delete a[class^="delete"]').live('click', function(){return false;});
});