触发两个连续的快速悬停以模拟CSS / JQUERY中的脉冲效果

I am developing a timeline css/jquery module, each time-node/checkpoint is represented by three concentric circles, when the scrolling reaches the checkpoint or when mouse hovers on it, the outer/third circle shows up by changing its background-color, on the hover event, and fades-out by changing its background color to the color of its outer div.I am developing a timeline css/jquery module, e