$('html, body').animate({ scrollTop: 0 }, 'fast');//帶動畫        $('html,body').scrollTop(0); //不帶動畫

  $(window).scroll(function () {            //You've scrolled this much:               $('p').text("You've scrolled " + $(window).scrollTop() + " pixels");        });

 <a name="top">top</a>            <a href="#top">Click here go back to the top.</a>

 var body = document.body,            html = document.documentElement;        var height = Math.max( body.scrollHeight, body.offsetHeight,                       html.clientHeight, html.scrollHeight, html.offsetHeight );       // 或者        var height = $(document).height();

var wheight = $(window).height();

<!-- 側邊欄 按鈕-->        <div id="back-top">		  <button class="styled-button">TOP</button>		</div>		<div id="back-end">		  <button class="styled-button">TOP</button>		</div>		<!--底部 內容-->        <div id="footer"></div>

jQuery(document).ready(function($){    /**     * 回到頂部     */    $('#back-top').click(function(){        $('html,body').stop();        $('html,body').animate({            scrollTop:'0px'        },1000);    });        /**     * 回到底部     */    $('#back-end').click(function(){        $('html,body').stop();        $('html,body').animate({            scrollTop:$('#footer').offset().top        },1000);    });});

//回到頂部的 顯示 隱藏代碼		   $(document).ready(function(){			  // hide #back-top first			  $("#back-top").hide();			  // fade in #back-top			  $(function () {			    $(window).scroll(function () {			      if ($(this).scrollTop() > 100) {			        $('#back-top').fadeIn();			      } else {			        $('#back-top').fadeOut();			      }			    });			    // scroll body to 0px on click			    $('#back-top').click(function () {			      $('body,html').animate({			        scrollTop: 0			      }, 'fast');			      return false;			    });			  });			});

#back-top{position: fixed; bottom:20px; right: 2%; z-index: 100; }