给这个图片添加摄像头图标，并获取图标的坐标值，也就是图标的css样式是positon:absolute,获取left和top的值。
思路是这样的，获取这里的长度，
1.鼠标点击时距浏览器的左边距离和上边距离，相当于(0,0)坐标
let x = e.clientX;
let y = e.clientY;2.图片距浏览器顶部的距离
let imgTop = $('.imageBox img').offset().top;
let imgLeft = $('.imageBox img').offset().left;3.就能获取到图片2中箭头的距离，即鼠标点击的位置距背景图顶部的距离
let cursorTop = y - imgTop;
let cursorLeft = x - imgLeft;4.计算得出图标的left和top值，这里是%。
let width = $('.imageBox img').width();
let height = $('.imageBox img').height();
let left = (cursorLeft/width*100).toFixed(2)
let top = (cursorTop/height*100).toFixed(2)5.效果如下图，但是鼠标点击处是图标的左上角，感觉好像是差一点
6.应该让鼠标点击处是图标的中心，就需要获取图标中心的坐标，然后 减去图片2中箭头的距离。
//设置添加的小图标的center为中心点
let pointLeft = $('.imageBox .block').width()*0.5;
let pointTop = $('.imageBox .block').height()*0.5;//鼠标点击无差距
let xData = cursorLeft - pointLeft;
let yData = cursorTop - pointTop;
7. 完整代码如下
<!DOCTYPE html>
<html><head><meta charset="utf-8"><title></title><style>.imageBox{width: 800px;position: relative;overflow: hidden;margin: 5% 2%;}.imageBox img{width: 100%;height: 100%;}.imageBox .block{width: 3%;height: 4%;background: url(camera.png) 0 0 no-repeat;background-size: 100% 100%;position: absolute;}</style></head><body><div class="page"><div class="imageBox"><img src="https://img0.baidu.com/it/u=3593454291,2854711423&fm=253&fmt=auto&app=138&f=JPEG?w=800&h=500" ><div class="block"></div></div></div><script src="jquery.min.js" type="text/javascript" charset="utf-8"></script><script type="text/javascript">$('.imageBox').click(function(e){//鼠标点击时距浏览器的左边距离和上边距离，相当于(0,0)坐标let x = e.clientX;let y = e.clientY;//图片的宽高let width = $('.imageBox img').width();let height = $('.imageBox img').height();//图片距浏览器顶部的距离let imgTop = $('.imageBox img').offset().top;let imgLeft = $('.imageBox img').offset().left;//鼠标点击的位置距背景图顶部的距离let cursorTop = y - imgTop;let cursorLeft = x - imgLeft;//设置添加的小图标的center为中心点let pointLeft = $('.imageBox .block').width()*0.5;let pointTop = $('.imageBox .block').height()*0.5;//鼠标点击无差距let xData = cursorLeft - pointLeft;let yData = cursorTop - pointTop;let left = (xData/width*100).toFixed(2)let top = (yData/height*100).toFixed(2)console.log(x);console.log(y);// let html = `<div class="block" style="top: ${top}%;left: ${left}%;"></div>`// $('.imageBox').append(html);$('.imageBox .block').css({'top':top+'%'})$('.imageBox .block').css({'left':left+'%'})})</script></body>
</html>
