点击返回顶部

function goTop(acceleration, time) {    acceleration = acceleration || 0.1;    time = time || 16;    var x1 = 0;    var y1 = 0;    var x2 = 0;    var y2 = 0;    var x3 = 0;    var y3 = 0;    if (document.documentElement) {      x1 = document.documentElement.scrollLeft || 0;      y1 = document.documentElement.scrollTop || 0;    }    if (document.body) {      x2 = document.body.scrollLeft || 0;      y2 = document.body.scrollTop || 0;    }    var x3 = window.scrollX || 0;    var y3 = window.scrollY || 0;    // 滚动条到页面顶部的水平距离    var x = Math.max(x1, Math.max(x2, x3));    // 滚动条到页面顶部的垂直距离    var y = Math.max(y1, Math.max(y2, y3));    // 滚动距离 = 目前距离 / 速度, 因为距离原来越小, 速度是大于 1 的数, 所以滚动距离会越来越小    var speed = 1 + acceleration;    window.scrollTo(Math.floor(x / speed), Math.floor(y / speed));    // 如果距离不为零, 继续调用迭代本函数    if (x > 0 || y > 0) {      var invokeFunction = "goTop(" + acceleration + ", " + time + ")";      window.setTimeout(invokeFunction, time);    }  }  $("#back2top").on("click", function() {    //$("body").scrollTop(0);    //window.scrollTo(0,0);    goTop();  });

 

zepto滚动到某个位置

$.fn.scrollTo = function(options) {  var defaults = {    toT: 0, //滚动目标位置    durTime: 500, //过渡动画时间    delay: 30, //定时器时间    callback: null //回调函数  };  var opts = $.extend(defaults, options),    timer = null,    _this = this,    curTop = _this.scrollTop(), //滚动条当前的位置    subTop = opts.toT - curTop, //滚动条目标位置和当前位置的差值    index = 0,    dur = Math.round(opts.durTime / opts.delay),    smoothScroll = function(t) {      index++;      var per = Math.round(subTop / dur);      if (index >= dur) {        _this.scrollTop(t);        window.clearInterval(timer);        if (opts.callback && typeof opts.callback == 'function') {          opts.callback();        }        return;      } else {        _this.scrollTop(curTop + index * per);      }    };  timer = window.setInterval(function() {    smoothScroll(opts.toT);  }, opts.delay);  return _this;};