使用电脑逛淘宝，京东等商城时，将鼠标移入图片中，图片会放大，之前一直在想这种是怎么实现的，前两天刚写出来，纯js实现的，无任何工具库。下面先来看下思路吧！刚学js的时候可能对于布局不是很重要，但学到面向对象编程后，布局就变得很重要了，有时候布局会影响到整体效果；先来看下布局吧！
<div class="photo">
<div class="sbox">
<img src="http://img0.imgtn.bdimg.com/it/u=4175582523,2707192513&fm=15&gp=0.jpg">
<span></span>
</div>
<div class="bbox">
<img src="http://img0.imgtn.bdimg.com/it/u=4175582523,2707192513&fm=15&gp=0.jpg">
</div>
<div class="nav">
<span> <</span>
<img src="http://img0.imgtn.bdimg.com/it/u=4175582523,2707192513&fm=15&gp=0.jpg" class="selected">
<img src="http://img4.imgtn.bdimg.com/it/u=181188734,374783636&fm=15&gp=0.jpg">
<img src="http://img2.imgtn.bdimg.com/it/u=2136674516,3472494802&fm=15&gp=0.jpg">
<img src="http://img0.imgtn.bdimg.com/it/u=3344949169,188332301&fm=15&gp=0.jpg">
<span>></span>
</div>
</div>
<style>
.photo {
width: 98%;
height: 500px;
margin: 20px auto;
border: 1px solid black;
position: relative;
}
.sbox {
width: 600px;
height: 300px;
position: absolute;
top: 20px;
left: 20px;
}
.sbox img {
width: 600px;
height: 300px;
}
.sbox span {
position: absolute;
background-color: rgba(199, 199, 199, .5);
top: 0;
display: none;
left: 0;
}
.bbox {
width: 600px;
height: 300px;
overflow: hidden;
position: absolute;
top: 20px;
left: 630px;
display: none;
}
.bbox img {
width: 1200px;
height: 600px;
position: absolute;
top: 0;
left: 0;
}
.nav {
width: 300px;
height: 32px;
position: absolute;
overflow: hidden;
bottom: 20px;
left: 20px;
}
.nav img {
width: 60px;
height: 30px;
border: 1px solid #dddddd;
}
.nav img:first-of-type {
margin-left: 20px;
}
.nav span {
position: absolute;
width: 16px;
height: 32px;
text-align: center;
line-height: 30px;
background-color: #cccccc;
top: 0;
cursor: pointer;
}
.nav span:last-child {
right: 0;
}
.nav .selected {
border: 1px solid #e48c63;
}
</style>布局就搞定了，比较简单的哈。下面就是一个思路吧
- 选择元素
- 鼠标进入
- 显示span和大图
- 计算span的宽高
- 鼠标移出
- 隐藏span和大图
- 鼠标移动
- span跟随鼠标移动
- span的边界限定
- 计算比例
- 大图跟随小图移动
大体思路就是这样的，个人建议是根据思路直接自己写，实在不会可以参照我的代码哈！因为自己写出来的和看了别人代码再写出来的感觉不太一样的。好啦，下面就是js部分的代码！
<script>
// 创建函数
function Big() {
// 获取元素
this.span = document.querySelector(".sbox span");
this.sbox = document.querySelector(".sbox");
this.bbox = document.querySelector(".bbox");
this.simg = document.querySelector(".sbox img");
this.bimg = document.querySelector(".bbox img");
this.img = document.querySelectorAll(".nav img");
this.init();
}
Big.prototype.init = function () {
// this的指向问题
var that = this;
for (var i = 0; i < this.img.length; i++) {
this.img[i].index = i;
// 点击导航图
this.img[i].onclick = function () {
for (var j = 0; j < that.img.length; j++) {
// 清除默认样式
that.img[j].className = "";
}
// 给当前的图片加样式
that.img[this.index].className = "selected";
that.index = this.index;
// 将当前图放入主体框中
that.changeImg();
}
}
// 鼠标移入事件
this.sbox.onmouseover = function () {
// 显示
that.span.style.display = "block";
that.bbox.style.display = "block";
// 计算span宽高
that.span.style.width = that.bbox.offsetWidth / that.bimg.offsetWidth * that.sbox.offsetWidth + "px";
that.span.style.height = that.bbox.offsetHeight / that.bimg.offsetHeight * that.sbox.offsetHeight + "px";
}
// 鼠标移动
this.sbox.onmousemove = function () {
that.move();
}
// 鼠标移出
this.sbox.onmouseout = function () {
// 隐藏
that.span.style.display = "none";
that.bbox.style.display = "none";
}
}
// 改变图片
Big.prototype.changeImg = function () {
this.simg.src = this.img[this.index].src;
this.bimg.src = this.img[this.index].src;
}
// 移动
Big.prototype.move = function () {
this.span.style.left = event.clientX - this.sbox.offsetLeft - this.span.offsetWidth / 2 + "px";
this.span.style.top = event.clientY - this.sbox.offsetTop - this.span.offsetHeight / 2 + "px";
// 边界限定
if (this.span.offsetLeft < 0) {
this.span.style.left = 0;
}
if (this.span.offsetTop < 0) {
this.span.style.top = 0;
}
if (this.span.offsetLeft > this.sbox.offsetWidth - this.span.offsetWidth) {
this.span.style.left = this.sbox.offsetWidth - this.span.offsetWidth + "px";
}
if (this.span.offsetTop > this.sbox.offsetHeight - this.span.offsetHeight) {
this.span.style.top = this.sbox.offsetHeight - this.span.offsetHeight + "px";
}
// 计算比例
var num=this.bbox.offsetWidth/this.bimg.offsetWidth;
console.log(num);
// 大图移动
this.bimg.style.left=-(this.span.offsetLeft/num)+"px";
this.bimg.style.top=-(this.span.offsetTop/num)+"px";
}
new Big();
</script>本文内容仅供个人学习、研究或参考使用，不构成任何形式的决策建议、专业指导或法律依据。未经授权，禁止任何单位或个人以商业售卖、虚假宣传、侵权传播等非学习研究目的使用本文内容。如需分享或转载，请保留原文来源信息，不得篡改、删减内容或侵犯相关权益。感谢您的理解与支持！