docs: function( data ){
  		data = $.extend({
  			distance: drag.distance,
  			which: drag.which,
  			not: drag.not,
  			drop: drag.drop
  			}, data || {});
  		data.distance = squared( data.distance ); //  x² + y² = distance²
  		$event.add( this, "mousedown", handler, data );
  		if ( this.attachEvent ) this.attachEvent("ondragstart", dontStart ); // prevent image dragging in IE...
  		}