<style>
      body,
      div {
        margin: 0;
        padding: 0;
      }
      .product {
        position: relative;
        width: 400px;
        height: 400px;
        margin: 50px 0 0 20px;
        border: 1px solid #000;
      }
      .preview_img img {
        width: 300px;
        height: 300px;
        margin: 50px 50px;
      }
      .mask {
        position: absolute;
        display: none;
        top: 20px;
        left: 30px;
        width: 80px;
        height: 80px;
        background-color: yellow;
        opacity: 0.5;
        cursor: move;
      }
      .big {
        position: absolute;
        display: none;
        left: 410px;
        top: 0;
        width: 500px;
        height: 500px;
        z-index: 999;
        overflow: hidden;
      }
      .big img {
        position: absolute;
        top: 0;
        left: 0;
        width: 400px;
        height: 400px;
      }
    </style>
    <!-- 引入js文件 -->
    <script src="detail.js"></script>
  </head>
  <body>
    <div class="product">
      <div class="preview_img">
        <img src="images/xs.jpg" alt="" />
        <div class="mask"></div>
        <div class="big">
          <img src="images/xs.jpg" alt="" class="bigImg" />
        </div>
      </div>
    </div>
</body>

JS頁(yè)面

//頁(yè)面預(yù)加載
window.addEventListener("load", function () {
  var preview_img = document.querySelector(".preview_img");
  var mask = document.querySelector(".mask");
  var big = document.querySelector(".big");

  //1.鼠標(biāo)經(jīng)過(guò) preview_img 就顯示和隱藏 mask 遮擋層 和 big 大盒子
  preview_img.addEventListener("mouseover", function () {
    mask.style.display = "block";
    big.style.display = "block";
  });
  preview_img.addEventListener("mouseout", function () {
    mask.style.display = "none";
    big.style.display = "none";
  });
  //把鼠標(biāo)坐標(biāo)給遮擋層是不合適的，因?yàn)檎趽鯇幼鴺?biāo)以父盒子為準(zhǔn)
  preview_img.addEventListener("mousemove", function (e) {
    //（1）先計(jì)算出鼠標(biāo)在盒子內(nèi)的坐標(biāo)
    var x = e.pageX - this.offsetLeft;
    var y = e.pageY - this.offsetTop;
    //（2）減去盒子高度寬度的一半
    //（3）mask 移動(dòng)的距離
    var maskX = x - mask.offsetWidth / 2;
    var maskY = y - mask.offsetHeight / 2;
    //(4)如果坐標(biāo)小于0 就讓他停在 0 的位置(即超出盒子范圍就停止)
    var egdeX = preview_img.offsetWidth - mask.offsetWidth;
    var egdeY = preview_img.offsetHeight - mask.offsetHeight;
    if (maskX <= 0) {
      maskX = 0;
    } else if (maskX >= egdeX) {
      maskX = egdeX;
    }
    if (maskY <= 0) {
      maskY = 0;
    } else if (maskY >= egdeY) {
      maskY = egdeY;
    }
    mask.style.left = maskX + "px";
    mask.style.top = maskY + "px";
    //大圖片的移動(dòng)距離 = 遮擋層移動(dòng)距離*大圖片最大移動(dòng)距離 / 遮擋層的最大移動(dòng)距離
    var bigImg = document.querySelector(".bigImg");
    //大圖片最大移動(dòng)距離
    var bigMax = bigImg.offsetWidth - big.offsetWidth;
    //大圖片的移動(dòng)距離 x y
    var bigX = (maskX * bigMax) / egdeX;
    var bigY = (maskY * bigMax) / egdeY;
    bigImg.style.left = -bigX + "px";
    bigImg.style.top = -bigY + "px";
  });
});

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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