simple draggable using jquery

gistfile1.js

/**
 * usage:
 *    $('div').draggable();
 *    $('*').draggable();
 */

$.fn.draggable = function() {
  var $document = $(document)
    , mouse = { update: function(e) {this.x = e.pageX; this.y = e.pageY;} };
    
  return this.each(function(){
    var $elem = $(this);
    $elem.bind('mousedown.drag', function(e) {
      mouse.update(e);
      if ( !/^(relative|absolute)$/.test($elem.css('position') ) ) {
        $elem.css('position', 'relative');
      }
      $document.bind('mousemove.drag', function(e) {
        $elem.css({
          left: (parseInt($elem.css('left'))||0) + (e.pageX - mouse.x) + 'px',
          top: (parseInt($elem.css('top'))||0) +  (e.pageY - mouse.y) + 'px'
        });
        mouse.update(e);
        e.preventDefault();
      });
      $document.one('mouseup.drag', function(e) {
        $document.unbind('mousemove.drag');
      });
      e.preventDefault();
    });  
  });
}