PC端JS輪播圖(自動+手動)
阿新 • • 發佈:2021-01-19
技術標籤:js
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>最簡單的輪播效果</title>
<style>
* {
margin: 0;
padding: 0
}
.box {
width: 500px;
height: 300px;
border: 1px solid #ccc;
margin: 100 px auto;
padding: 5px;
}
.inner {
width: 500px;
height: 300px;
position: relative;
overflow: hidden;
}
.inner img {
width: 500px;
height: 300px;
vertical-align: top
}
ul {
width: 1000%;
position: absolute;
list-style: none;
left: 0;
top: 0 ;
}
.inner li {
float: left;
}
ol {
position: absolute;
height: 20px;
right: 20px;
bottom: 20px;
text-align: center;
padding: 5px;
}
ol li {
display: inline-block;
width: 20px;
height: 20px;
line-height: 20px;
background-color: #fff;
margin: 5px;
cursor: pointer;
}
ol .current {
background-color: red;
}
#arr {
display: none;
}
#arr span {
width: 40px;
height: 40px;
position: absolute;
left: 5px;
top: 50%;
margin-top: -20px;
background: #fff;
cursor: pointer;
line-height: 40px;
text-align: center;
font-weight: bold;
font-family: '黑體';
font-size: 30px;
color: #000;
opacity: 0.5;
border: 1px solid #fff;
}
#arr #right {
right: 5px;
left: auto;
}
</style>
</head>
<body>
<div class="box" id="box">
<div class="inner">
<!--輪播圖-->
<ul>
<li><a href="#"><img src="img/01.jpg" alt=""></a></li>
<li><a href="#"><img src="img/02.jpg" alt=""></a></li>
<li><a href="#"><img src="img/03.jpg" alt=""></a></li>
</ul>
<ol class="bar">
</ol>
<!--左右焦點-->
<div id="arr">
<span id="left">
<</span> <span id="right">>
</span>
</div>
</div>
</div>
</body>
<script>
function my$(id) {
return document.getElementById(id);
}
//獲取各元素,方便操作
var box = my$("box");
var inner = box.children[0];
var ulObj = inner.children[0];
var list = ulObj.children;
var olObj = inner.children[1];
var arr = my$("arr");
var imgWidth = inner.offsetWidth;
var right = my$("right");
var pic = 0;
//根據li個數,建立小按鈕
for (var i = 0; i < list.length; i++) {
var liObj = document.createElement("li");
olObj.appendChild(liObj);
liObj.innerText = (i + 1);
liObj.setAttribute("index", i);
//為按鈕註冊mouseover事件
liObj.onmouseover = function() {
//先清除所有按鈕的樣式
for (var j = 0; j < olObj.children.length; j++) {
olObj.children[j].removeAttribute("class");
}
this.className = "current";
pic = this.getAttribute("index");
animate(ulObj, -pic * imgWidth);
}
}
//設定ol中第一個li有背景顏色
olObj.children[0].className = "current";
//克隆一個ul中第一個li,加入到ul中的最後=====克隆
ulObj.appendChild(ulObj.children[0].cloneNode(true));
var timeId = setInterval(onmouseclickHandle, 3000);
//左右焦點實現點選切換圖片功能
box.onmouseover = function() {
arr.style.display = "block";
clearInterval(timeId);
};
box.onmouseout = function() {
arr.style.display = "none";
timeId = setInterval(onmouseclickHandle, 3000);
};
right.onclick = onmouseclickHandle;
function onmouseclickHandle() {
//如果pic的值是5,恰巧是ul中li的個數-1的值,此時頁面顯示第六個圖片,而使用者會認為這是第一個圖,
//所以,如果使用者再次點選按鈕,使用者應該看到第二個圖片
if (pic == list.length - 1) {
//如何從第6個圖,跳轉到第一個圖
pic = 0; //先設定pic=0
ulObj.style.left = 0 + "px"; //把ul的位置還原成開始的預設位置
}
pic++; //立刻設定pic加1,那麼此時使用者就會看到第二個圖片了
animate(ulObj, -pic * imgWidth); //pic從0的值加1之後,pic的值是1,然後ul移動出去一個圖片
//如果pic==5說明,此時顯示第6個圖(內容是第一張圖片),第一個小按鈕有顏色,
if (pic == list.length - 1) {
//第五個按鈕顏色幹掉
olObj.children[olObj.children.length - 1].className = "";
//第一個按鈕顏色設定上
olObj.children[0].className = "current";
} else {
//幹掉所有的小按鈕的背景顏色
for (var i = 0; i < olObj.children.length; i++) {
olObj.children[i].removeAttribute("class");
}
olObj.children[pic].className = "current";
}
}
left.onclick = function() {
if (pic == 0) {
pic = list.length - 1;
ulObj.style.left = -pic * imgWidth + "px";
}
pic--;
animate(ulObj, -pic * imgWidth);
for (var i = 0; i < olObj.children.length; i++) {
olObj.children[i].removeAttribute("class");
}
//當前的pic索引對應的按鈕設定顏色
olObj.children[pic].className = "current";
};
//設定任意的一個元素,移動到指定的目標位置
function animate(element, target) {
clearInterval(element.timeId);
//定時器的id值儲存到物件的一個屬性中
element.timeId = setInterval(function() {
//獲取元素的當前的位置,數字型別
var current = element.offsetLeft;
//每次移動的距離
var step = 10;
step = current < target ? step : -step;
//當前移動到位置
current += step;
if (Math.abs(current - target) > Math.abs(step)) {
element.style.left = current + "px";
} else {
//清理定時器
clearInterval(element.timeId);
//直接到達目標
element.style.left = target + "px";
}
}, 10);
}
</script>
</html>