code: function (el, params, options) {
  			var $el = $(el);
  			if (!el.style) {
  				el.style = {}; // #1881
  			}
  			if (params.d) {
  				el.toD = params.d; // keep the array form for paths, used in $.fx.step.d
  				params.d = 1; // because in jQuery, animating to an array has a different meaning
  			}
  	
  			$el.stop();
  			if (params.opacity !== UNDEFINED && el.attr) {
  				params.opacity += 'px'; // force jQuery to use same logic as width and height (#2161)
  			}
  			$el.animate(params, options);
  	
  		}
docs: Animate a HTML element or SVG element wrapper
  @param {Object} el
  @param {Object} params
  @param {Object} options jQuery-like animation options: duration, easing, callback