jQuery模拟物体自由落体运动(附演示与demo源码下载)

wangtao

2016-01-21

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本文实例讲述了jQuery模拟物体自由落体运动的方法。分享给大家供大家参考，具体如下：

运行效果截图如下：

jQuery模拟物体自由落体运动(附演示与demo源码下载)

点击此处查看在线演示效果。

完整实例代码点击此处本站下载。

具体代码如下：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
 <title>自由落体</title>
 <script src="jquery-1.7.1.min.js" type="text/javascript"></script>
 <script type="text/javascript" >
  $(document).ready(function () {
  });
  var all_Height = 500;
  var a = 9.8; // 加速度
  var v = 0;
  var prev_Time = 0;
  var prev_Speed = 0;
  var prev_Height = 0;
  var speed = 0;
  // 获取当前的高度
  var getHeight = function (obj) {
   return obj.offset().top;
  }
  // 获取当前的速度
  var getSpeed = function (time, a) {
   return time * a;
  }
  // 向下走时获得当前物体所走的路径
  var getCurrentHeight = function (time) {
   return 1 / 2 * a * time * time;
  }
  // 向上走时获得当前物体所走的路径
  var getCurrentHeight2 = function (speed, time) {
   return speed * time - 1 / 2 * a * time * time;
  }
  // 向下跑
  function down() {
   prev_Time = 0;
   var interval = setInterval(function () {
    if (getHeight($(".obj")) < all_Height) {
     prev_Time = prev_Time + 0.1;
     var height = getCurrentHeight(prev_Time) + prev_Height;
     $(".obj").css("top", height + "px");
     $(".info").append("<div>" + height + "</div>");
    } else {
     speed = getSpeed(a, prev_Time);
     prev_Speed = speed;
     clearInterval(interval);
     up();
    }
   }, 5);
  }
  // 向上跑
  function up() {
   prev_Time = 0;
   prev_Speed -= 4; // 动能损耗
   var interval = setInterval(function () {
    if (speed > 0) {
     speed = prev_Speed - getSpeed(a, prev_Time);
     prev_Time = prev_Time + 0.1;
     var height = all_Height - getCurrentHeight2(prev_Speed, prev_Time);
     $(".obj").css("top", height + "px");
    } else {
     clearInterval(interval);
     prev_Height = $(".obj").offset().top;
     if (prev_Height < all_Height) {
      down();
     }
    }
   }, 5);
  }
  function play() {
   alert('play');
   down();
   document.getElementById("obj").onclick = null;
  }
 </script>
 <style type="text/css">
 body{ margin:0 0 0 0 ; background:#FFFFFF;}
 .title { text-align:center; color:#666666; border-bottom:2px solid gray; font-size:30px; line-height:100px; font-weight:bolder;}
 .obj { background-image:url('a.jpg'); width:50px; height:50px; position:absolute; top:0; left:0; }
 </style>
</head>
<body>
<div style="height:550px; border-bottom:2px solid gray;">
<div class="title" >自由落体大模拟<span style="font-size:12px;">(点击图片让它落下)</span></div>
</div>
<div class="obj" id="obj" onclick="play();" ></div>
</body>
</html>

更多关于js运动相关内容感兴趣的读者可查看本站专题：《JavaScript运动效果与技巧汇总》

希望本文所述对大家jQuery程序设计有所帮助。

jquery var 自由落体运动 speed