實現圖片首尾平滑輪播(JS原生方法―節流)

2019-11-19 15:09:39

字體：大中小

來源：轉載

供稿：網友

首先給出HTML代碼，要注意輪播圖片表(#list)末尾加上第一個圖片1.jpg，在首部加上最后一個圖片5.jpg。

<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>首尾輪播</title> <link rel="stylesheet" href="首尾輪播.css" rel="external nofollow" ><script src="首尾輪播.js"></script></head><body> <div id="container">  <div id="list">   <div><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="../imgs/5.jpg" alt=""></a></div>   <div><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="../imgs/1.jpg" alt=""></a></div>   <div><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="../imgs/2.jpg" alt=""></a></div>   <div><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="../imgs/3.jpg" alt=""></a></div>   <div><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="../imgs/4.jpg" alt=""></a></div>   <div><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="../imgs/5.jpg" alt=""></a></div>   <div><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="../imgs/1.jpg" alt=""></a></div>  </div>  <div class="arrow" id="prev"><</div>  <div class="arrow" id="next">></div> </div>  </body> </html>

接下來給出css和js代碼，大家可以酌情根據圖片的大小、數量、寬度，調整container、list的參數，這也是封裝JS所要考慮的參數。

*{ margin: 0; padding: 0;}#container{ height: 400px; width: 500px; margin: 0 auto; position: relative; overflow: hidden; border: 1px solid black;}#list>div { float: left;}#list{ position: absolute;  height: 400px; width: 3600px; }#list img{ height: 400px; width: 500px;}.arrow { user-select:none; position: absolute; top:150px; z-index: 2; background-color: #aaa; height: 100px; width: 80px; cursor: pointer; opacity: 0.5; display: none; line-height: 100px; text-align: center; color: #222; font-size: 3em;}#container:hover .arrow{ display: block;} #prev{ left:20px;} #next{ right: 20px;}

在JS中，我們可以通過改變speed變量來控制圖片切換的速度....這里用的是 element.style.transition來控制的過渡效果.

window.onload=function(){ var container = document.getElementById('container'); var list = document.getElementById('list');//獲取圖片容器 var prev = document.getElementById('prev');//向前按鈕 var next = document.getElementById('next');//向后按鈕 var nowP = 1; //顯示位置 var judge = null; //執行權 var speed = 0.1; // 切換速度 秒 prev.onclick=function(){  if(!judge){    judge = setTimeout(function(){     if(nowP==1){setTimeout(function(){      list.style.transition="left 0s";     list.style.left = "-2500px";　     nowP = 5;},speed*1000);} //當到達圖片表左邊緣時與動畫同步切換      list.style.transition = "left "+speed+"s";    move(500);    nowP--;    judge = null;   },speed*1000);  } }; next.onclick=function(){  if(!judge){        judge = setTimeout(function(){     if(nowP==5){setTimeout(function(){      list.style.transition="left 0s";     list.style.left = "-500px";      nowP = 1;},speed*1000);} //當到達圖片表右邊緣時與動畫同步切換     list.style.transition = "left "+speed+"s";    move(-500);    nowP++;    judge = null;   },speed*1000);  } }; function move(num){  var term = parseInt(list.style.left) + num ;   list.style.left = term+"px"; } var roll= setInterval(function(){  next.onclick(); },2000); container.onmouseenter=function(){  clearInterval(roll); }; container.onmouseleave=function()  {  roll=setInterval(function(){  next.onclick();  },2000); }; };

下面是一個演示demo，簡單來說原理就是在切換到圖片表首和表尾的動畫開始時，設置一個延遲執行時間與動畫過渡時間相同的setTimeout函數來執行瞬間切換，再通過節流來保證最大的切換速度(speed)。

本人也是初學前端，如果有幫助的話，點一下推薦吧