3个JQuery实现浮动按钮返回页面顶部，6个JS实现的，还有一个仿QQ空间的返回顶部浮动按钮。示例多，按钮样式多，返回动作有平滑返回，设置速度快慢。-Top 3 JQuery floating button to return to the top of the page 6 JS implementation, as well as an imitation QQ space floating button. More example, button style, smooth return