原生js实现无缝轮播
因为要做到无缝，所以就要把第一张图片和最后一张连接起来，在此处采用js克隆了第一张图片的节点，添加到最后，显示图片序号的小圆按钮也是使用js动态添加的。
- html部分
<div class="banner" id="banner">
<ul class="pic" id="pic">
<li><a href="javascript:void(0)"><img src="data:images/1.jpg"></a></li>
<li><a href="javascript:void(0)"><img src="data:images/2.png"></a></li>
<li><a href="javascript:void(0)"><img src="data:images/3.png"></a></li>
<li><a href="javascript:void(0)"><img src="data:images/4.png"></a></li>
<li><a href="javascript:void(0)"><img src="data:images/5.jpg"></a></li>
<li><a href="javascript:void(0)"><img src="data:images/6.png"></a></li>
<li><a href="javascript:void(0)"><img src="data:images/7.png"></a></li>
</ul>
<ul class="dot" id="dot"></ul>
<button class="left" id="leftBtn"><</button>
<button class="right" id="rightBtn">></button>
</div> - css部分
* {
padding:;
margin:;
}
.banner {
width: 1000px;
height: 600px;
margin: 0 auto;
position: relative;
overflow: hidden;
}
ul, li {
list-style: none;
}
.pic {
height: 600px;
position: absolute;
left:;
top:;
}
.pic li {
float: left;
}
.pic li img {
width: 1000px;
height: 600px;
}
.dot {
width: 100%;
text-align: center;
font-size:;
position: absolute;
bottom: 40px;
left:;
}
.dot li {
display: inline-block;
width: 10px;
height: 10px;
border-radius: 50%;
background-color: #fff;
margin: 0 5px;
cursor: pointer;
}
.banner button {
width: 30px;
height: 50px;
background-color: rgba(0, 0, 0, .5);
border: 0 none;
color: #fff;
opacity: .5;
position: absolute;
top: 45%;
cursor: pointer;
font-size: 24px;
}
.left {
left:;
}
.right {
right:;
} - js部分
js中有封装的一些方法，包括查看对象属性的兼容写法，动画函数（该方法实现了height,width,left,top,opacity等属性的动画效果），和通过事件冒泡找寻节点的函数；var leftBtn = document.getElementById("leftBtn");
var rightBtn = document.getElementById("rightBtn");
var banner = document.getElementById("banner");
var pic = document.getElementById("pic");
var dot = document.getElementById("dot");
for (var i = 0; i < pic.children.length; i++) {
var node = document.createElement("LI");
node.index = i;
dot.appendChild(node);
}
var copy = pic.children[0].cloneNode(true);
pic.appendChild(copy);
var width = parseInt(getStyle(pic.children[0], "width"));
var len = pic.children.length;
pic.style.width = width * len + "px";
var index = 0;
var t;
function move() {
if(index == len) {
pic.style.left = 0;
index = 1;
}
if (index == -1) {
pic.style.left = -(len - 1) * width + "px";
index = len - 2;
}
left = -width * index;
changeDots(index);
animate(pic, {left, left}, function() {
t = setTimeout(function () {
index++;
if (index == len) {
pic.style.left = 0;
index = 1;
}
move();
}, 2000);
});
}
move();
// 为按钮添加点击事件
dot.onclick = function(e) {
e = e || window.event;
var target = e.target || e.srcElement;
target = getTarget(target, "tagName", "LI", this);
if (target) {
clearTimeout(t);
index = target.index;
changeDots(index);
move();
}
}
// 左右按钮
leftBtn.onclick = function() {
clearTimeout(t);
index--;
move();
}
rightBtn.onclick = function() {
clearTimeout(t);
index++;
move();
}
// 改变按钮颜色
function changeDots(index) {
if (index < 0) {
index = len;
}
if (index == len - 1) {
index = 0;
}
for (var i = 0; i < len - 1; i++) {
dot.children[i].style.backgroundColor = "#fff";
}
dot.children[index].style.backgroundColor = "red";
}
/**
* 查看ele对象的type属性
* @param {元素对象} ele
* @param {属性} type
*/
function getStyle(ele, type) {
if (ele.currentStyle) {
return ele.currentStyle[type];
} else {
return getComputedStyle(ele, null)[type];
}
}
/**
* 动画效果
* @param {元素对象} el
* @param {结束条件} endObj
* @param {回调函数} cb
* @param {时间} time
*/
function animate(el, endObj, cb, time) {
time = time || 200;
var startObj = {};
var _startObj = {};
var speedObj = {};
for (var i in endObj) {
startObj[i] = parseInt(getStyle(el, i));
_startObj[i] = startObj[i];
speedObj[i] = 16.7 * (endObj[i] - startObj[i]) / time;
}
var flag = false;
clearInterval(el.t);
el.t = setInterval(function() {
for (var j in endObj) {
startObj[j] += speedObj[j];
if (_startObj[j] < endObj[j] ? startObj[j] >= endObj[j] : startObj[j] <= endObj[j]) {
startObj[j] = endObj[j];
clearInterval(el.t);
flag = true;
}
if (j == "opacity") {
el.style[j] = startObj[j];
} else {
el.style[j] = startObj[j] + "px";
}
}
if (flag && cb) {
cb();
}
}, 16.7);
}
/**
* 找到attr属性为value的节点
* @param {目标对象，鼠标点击对象} target
* @param {属性名} attr
* @param {属性值} value
* @param {结束条件} end
*/
function getTarget(target, attr, value, end) {
while (target != end) { //如果鼠标点击的是end，则直接结束
if (target[attr] == value) { //如果点击的对象的attr属性值为value，则返回该对象
return target;
}
target = target.parentNode; //否则查找其父节点
}
}