jQuery可变透明度返回顶部代码，如果向下滚动超过1200像素，按钮的透明度会下降，减少视觉干扰，更便于浏览内容主体，非常贴心的用户体验，兼容主流浏览器，源码之家推荐下载！-jQuery variable transparency Top codes If you scroll down more than 1200 pixels, the transparency of the button will decrease, reduce visual interference, but eas