一个简单的放大镜demo

html部分：

<div class="web">
    <div class="goodsBox">
      <img src="./small.jpg" alt="" />
      <div class="mask"></div>
    </div>

    <div class="zoomBox">
      <img src="./big.jpg" alt="">
    </div>
  </div>

css部分：

@charset "utf-8";

* {
  margin: 0;
  padding: 0;
  text-decoration: none;
  list-style: none;
}

.web {
  padding: 50px;
}

.goodsBox {
  width: 350px;
  height: 350px;
  overflow: hidden;
  position: relative;

  /* 鼠标移入变化 */
  cursor: move;
}

.goodsBox>img {
  width: 100%;
}

.mask {
  display: none;

  position: absolute;
  width: 200px;
  height: 200px;
  background-color: rgba(255, 255, 0, 0.3);
  top: 0;
  left: 0;
  /* 使得元素节点忽略事件触发 事件穿透 */
  pointer-events: none;

}

.zoomBox {
  position: absolute;
  top: 0;
  left: 400px;

  width: 457px;
  height: 457px;
  overflow: hidden;
  display: none;
}

.zoomBox img {
  position: absolute;
  top: 0;
  left: 0;
}

js部分:

const goodsBoxNode = document.querySelector(".goodsBox");
const maskNode = document.querySelector(".mask");
const bigImg = document.querySelector(".zoomBox img");
const bigBox = document.querySelector(".zoomBox");

// 商品图片盒子高度
const goodsBoxHeight = goodsBoxNode.clientHeight;
// 商品图片盒子宽度
const goodsBoxWidth = goodsBoxNode.clientWidth;
// 遮罩层盒子高度
let maskHeight = 0;
// 遮罩层盒子宽度
let maskWidth = 0;

// 鼠标Y轴
let mouseY;
// 鼠标X轴
let mouseX;

// 鼠标在商品图片框中移动事件
goodsBoxNode.addEventListener("mousemove", (e) => {
  mouseX = e.layerX - maskWidth / 2;
  console.log(e.layerX);
  // console.log(maskWidth);
  if (mouseX < 0) {
    mouseX = 0;
  }

  if (mouseX > goodsBoxWidth - maskWidth) {
    mouseX = goodsBoxWidth - maskWidth;
  }

  maskNode.style.left = `${mouseX}px`;
  bigImg.style.left = `-${mouseX * (bigImg.clientWidth / goodsBoxWidth)}px`;

  mouseY = e.layerY - maskHeight / 2;
  if (mouseY < 0) {
    mouseY = 0;
  }
  if (mouseY > goodsBoxHeight - maskHeight) {
    mouseY = goodsBoxHeight - maskHeight;
  }
  maskNode.style.top = `${mouseY}px`;
  bigImg.style.top = `-${mouseY * (bigImg.clientHeight / goodsBoxHeight)}px`;
});

// 鼠标移入遮罩及放大图片出现
goodsBoxNode.addEventListener("mouseenter", () => {
  maskNode.style.display = "block";
  maskWidth = 200;
  maskHeight = 200;
  bigBox.style.display = "block";
});

// 鼠标移出遮罩及放大图片消失
goodsBoxNode.addEventListener("mouseleave", () => {
  maskNode.style.display = "none";
  bigBox.style.display = "none";
});

参考：https://blog.csdn.net/learner_boy/article/details/72190462

标签：style,const,放大镜,demo,none,mouseY,mouseX,简单,display
来源： https://www.cnblogs.com/echo42/p/15883806.html