x_slide.js

《Ajax 实战》中文（有源码）详细简介了ajax

// x_slide.js, part of X, a Cross-Browser.com Javascript Library
// Copyright (C) 2001,2002,2003,2004,2005 Michael Foster - Distributed under the terms of the GNU LGPL - OSI Certified
// File Rev: 3

function xSlideTo(e, x, y, uTime)
{
  if (!(e=xGetElementById(e))) return;
  if (!e.timeout) e.timeout = 25;
  e.xTarget = x; e.yTarget = y; e.slideTime = uTime; e.stop = false;
  e.yA = e.yTarget - xTop(e); e.xA = e.xTarget - xLeft(e); // A = distance
  if (e.slideLinear) e.B = 1/e.slideTime;
  else e.B = Math.PI / (2 * e.slideTime); // B = period
  e.yD = xTop(e); e.xD = xLeft(e); // D = initial position
  var d = new Date(); e.C = d.getTime();
  if (!e.moving) _xSlideTo(e);
}
function _xSlideTo(e)
{
  if (!(e=xGetElementById(e))) return;
  var now, s, t, newY, newX;
  now = new Date();
  t = now.getTime() - e.C;
  if (e.stop) { e.moving = false; }
  else if (t < e.slideTime) {
    setTimeout("_xSlideTo('"+e.id+"')", e.timeout);
    if (e.slideLinear) s = e.B * t;
    else s = Math.sin(e.B * t);
    newX = Math.round(e.xA * s + e.xD);
    newY = Math.round(e.yA * s + e.yD);
    xMoveTo(e, newX, newY);
    e.moving = true;
  }  
  else {
    xMoveTo(e, e.xTarget, e.yTarget);
    e.moving = false;
  }  
}