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| <!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>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
#div{ width: 100px;height: 100px;background: red;position: absolute;}
</style>
</head>
<script type="text/javascript">
var speedX = 6;
var speedY = 8;
const g = 3;
var timer = null;
function startMove(){
clearInterval(timer);
timer = setInterval(function() {
var oDiv = document.getElementById('div');
speedY += g;
var t = oDiv.offsetTop + speedY;
var l = oDiv.offsetLeft + speedX;
if (t >= document.documentElement.clientHeight - oDiv.offsetHeight) {
speedY *= -0.8;
speedX *= 0.8;
t = document.documentElement.clientHeight - oDiv.offsetHeight;
} else if(t <= 0) {
speedY *= -1;
speedX *= 0.8;
t = 0;
}
if (l >= document.documentElement.clientWidth - oDiv.offsetWidth) {
speedX *= -0.8;
l = document.documentElement.clientWidth - oDiv.offsetWidth;
} else if(l <= 0) {
speedX *= -0.8;
l = 0;
}
if (Math.abs(speedX) < 1) {
speedX = 0;
}
if (Math.abs(speedY) <1 ) {
speedY = 0;
}
if (speedX === 0
&& speedY === 0
&& t === document.documentElement.clientHeight - oDiv.offsetHeight) {
clearInterval(timer);
} else {
oDiv.style.top = t + 'px';
oDiv.style.left = l + 'px';
}
}, 30);
}
window.onload = function() {
var oDiv = document.getElementById('div');
var lastX = 0;
var lastY = 0;
oDiv.onmousedown = function(event) {
var disX = event.clientX - oDiv.offsetLeft;
var disY = event.clientY - oDiv.offsetTop;
document.onmousemove = function(event){
var l = event.clientX - disX;
var t = event.clientY - disY;
oDiv.style.top = t + 'px';
oDiv.style.left = l + 'px';
speedX = l - lastX;
speedY = t - lastY;
lastX = l;
lastY = t;
document.title = 'x:' + speedX + 'y:' + speedY;
}
document.onmouseup = function() {
document.onmousemove = null;
document.onmouseup = null;
startMove();
}
clearInterval(timer);
}
}
</script>
<body>
<div id="div"></div>
</body>
</html>
|