left值不一样
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>缓冲1</title>
<style type="text/css">
#div1{height: 200px;
width: 200px;
background: blue;
position: relative;
left: -200px;
}
#div1 span{ position: absolute;
height: 50px;
width: 15px;
left: 200px;
top: 75px;
background-color: red;
}
*{margin: 0;padding: 0;}
</style>
<script type="text/javascript">
window.onload=function () {
var div1=document.getElementById('div1');
div1.onmouseover=function(){
startmove(0);
}
div1.onmouseout=function(){
startmove(-200);
}
}
var timer=null;
function startmove (itarget) {
clearInterval(timer);
timer=setInterval(function(){
var speed=(itarget-div1.offsetLeft)/20;//speed赋值后,下边接着判断
speed=speed>0?Math.ceil(speed):Math.floor(speed);
if (itarget==div1.offsetLeft) {
clearInterval(timer);
} else{
div1.style.left=div1.offsetLeft+speed+'px';
};
},30)
}
</script>
</head>
<body>
<div id="div1">
<span>分享</span>
</div>
</body>
</html><!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>缓冲2</title>
<style type="text/css">
#div1{height: 200px;
width: 200px;
background: blue;
position: relative;
left: -200px;
}
#div1 span{ position: absolute;
height: 50px;
width: 15px;
left: 200px;
top: 75px;
background-color: red;
}
*{margin: 0;padding: 0;}
</style>
<script type="text/javascript">
window.onload=function () {
var div1=document.getElementById('div1');
div1.onmouseover=function(){
startmove(0);
}
div1.onmouseout=function(){
startmove(-200);
}
}
var timer=null;
function startmove (itarget) {
clearInterval(timer);
timer=setInterval(function(){//这里speed直接赋值并且判断
var speed=speed>0?Math.ceil((itarget-div1.offsetLeft)/20):Math.floor((itarget-div1.offsetLeft)/20);
if (itarget==div1.offsetLeft) {
clearInterval(timer);
} else{
div1.style.left=div1.offsetLeft+speed+'px';
};
},30)
}
</script>
</head>
<body>
<div id="div1">
<span>分享</span>
</div>
</body>
</html>两种speed的赋值方式,造成两种结果:第一段代码向右移动后的left值正常,能达到0;第二段代码向右移动后的left值是-19px.
周末00浏览 1574回答 2
2回答
-
echo_kinchao
逻辑出现了问题 -
忧郁的狮子座
因为19除以20等于0。因此，当offsetleft小于20，比如19的时候，speed就为0了，当然就不动咯。反过来增加的话，就不会出现这种情况。
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