javascript中级--运动三
一、缓冲运动
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
}
#div1 {
width: 100px;
height: 100px;
background: red;
position: absolute;
left: 0px;
}
#div2 {
width: 1px;
height: 300px;
background: black;
position: absolute;
left: 300px;
}
</style>
<script>
window.onload = function() {
}
var timer = null;
function starMove(iTarget) {
var oDiv = document.getElementById('div1');
clearInterval(timer); //防止定时器累加
timer = setInterval(function() {
var iSpeed = (iTarget - oDiv.offsetLeft) / 8;
//Math.ceil向上取整
//Math.floor向下取整
// if (iSpeed > 0) {
// iSpeed = Math.ceil(iSpeed);
// } else {
// iSpeed = Math.floor(iSpeed);
// }
iSpeed = iSpeed > 0 ? Math.ceil(iSpeed) : Math.floor(iSpeed);
if (oDiv.offsetLeft == iTarget) { //判断是否到达终点
clearInterval(timer); //清除定时器
} else {
oDiv.style.left = oDiv.offsetLeft + iSpeed + 'px';
}
}, 30);
}
</script>
</head>
<body>
<input type="button" name="" value="运动" onclick="starMove(300)">
<div id="div1"></div>
<div id="div2"></div>
</body>
</html>
二、滑动的侧边栏
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
}
#div1 {
width: 100px;
height: 100px;
background: red;
position: absolute;
right: 0px;
}
</style>
<script>
window.onscroll = function() {
var oDiv = document.getElementById('div1');
var scrollTop = document.documentElement.scrollTop || document.body.scrollTop;
// oDiv.style.top = scrollTop + (document.documentElement.clientHeight - oDiv.offsetHeight) / 2 + 'px';
var t = scrollTop + (document.documentElement.clientHeight - oDiv.offsetHeight) / 2;
startMove(parseInt(t));
}
var timer = null;
function startMove(iTarget) {
var oDiv = document.getElementById('div1');
clearInterval(timer);
timer = setInterval(function() {
var iSpeed = (iTarget - oDiv.offsetTop) / 8;
iSpeed = iSpeed > 0 ? Math.ceil(iSpeed) : Math.floor(iSpeed);
if (oDiv.offsetTop == iTarget) {
clearInterval(timer);
} else {
oDiv.style.top = oDiv.offsetTop + iSpeed + 'px';
}
}, 30);
}
</script>
</head>
<body style="height:1000000px;">
<div id="div1"></div>
</body>
</html>
