为什么判断语句写在点击事件函数体内没有效果？如果要写在点击事件函数体内该怎样写？
来源：4-1 无限滚动
慕数据5775487
2016-12-09 02:54
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
<style>
*{margin:0;padding:0;text-decoration:none;}
body{padding:20px}
#container{width:600px;height:400px;border:3px solid #333;overflow:hidden;position:relative;margin:0 auto;}
#list{width:4200px;height:400px;position:absolute;z-index:1;}
#list img{float:left;}
#buttons{position:absolute;width:100px;height:10px;bottom:20px;left:250px;z-index:2;}
#buttons span{cursor:pointer;display:block;float:left;width:10px;height:10px;border:1px solid #FFF;border-radius:50%;background:#333;margin-right:5px;}
.arrow{position:absolute;display:none;width:40px;height:40px;line-height:40px;z-index:2;font-size:36px;text-align:center;font-weight:bold;top:180px;background-color:rgba(0,0,0,.3);color:#FFF;}
#prev{left:20px;}
#next{right:20px;}
#container:hover .arrow{display:block;}
.arrow:hover{background-color:rgba(0,0,0,.7);}
</style>
<script>
window.onload = function(){
var container = document.getElementById('container');
var list = document.getElementById('list');
var buttons = document.getElementById('buttons').getElementsByTagName('span');
var prev = document.getElementById('prev');
var next = document.getElementById('next');
function animate(offset){
list.style.left=parseInt(list.style.left)+offset+'px';
}
next.onclick = function(){
animate(-600);
if(list.style.left<-3000){
list.style.left=-600+'px';
}
}
prev.onclick =function(){
animate(600);
if(list.style.left>-600){
list.style.left=-3000+'px';
}
}
}
</script>
</head>
<body>
<div id="container">
<div id="list" style="left:-600px">
<img src="img/5.jpg" alt="" title="">
<img src="img/1.jpg" alt="" title="">
<img src="img/2.jpg" alt="" title="">
<img src="img/3.jpg" alt="" title="">
<img src="img/4.jpg" alt="" title="">
<img src="img/5.jpg" alt="" title="">
<img src="img/1.jpg" alt="" title="">
</div>
<div id="buttons">
<span index="1" class="on"></span>
<span index="2" class=""></span>
<span index="3" class=""></span>
<span index="4" class=""></span>
<span index="5" class=""></span>
</div>
<a href="#" id="prev" class="arrow"><</a>
<a href="#" id="next" class="arrow">></a>
</div>
</body>
</html>
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2回答
-
- Pokeman
- 2016-12-09 23:33:03
function showButton(){ for(var i=0;i<buttons.length;i++){ buttons[i].className=''; } if(index>5){ index=1; } if(index<1){ index=5; } buttons[index].className='on'; }我是这样写的，不过点击事件函数里面index+=1和index-=1应该放在showButton();前面，如下
next.onclick=function(){
animate(-720);
index+=1;
showButton();
}
prev.onclick=function(){
animate(720);
index-=1;
showButton();
}
-
- 海的那边是海
- 2017-03-27 18:18:16
请问你的问题,该怎么解释呢,我也有相同的疑问,上面回答显然没答到点子上啊.
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