lovecoding
/
VIP28


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }

    #container {
      position: relative;
    }

    #smallBox {
      width: 400px;
      height: 400px;
    }

    #bigBox {
      width: 400px;
      height: 400px;
      overflow: hidden;
      position: absolute;
      left: 400px;
      top: 0;
      display: none;
    }

    #drag {
      width: 200px;
      height: 200px;
      background: rgba(0, 0, 0, 0.4);
      position: absolute;
      top: 0;
      left: 0;
      display: none;
    }

    #bigImg {
      position: absolute
    }
  </style>
</head>

<body>
  <div id="container">
    <div id="smallBox">
      <img src="images/1.jpg" alt="">
      <div id="drag"></div>
    </div>
    <div id="bigBox">
      <img src="images/2.jpg" alt="" id="bigImg">
    </div>
  </div>
  <script>
    var drag = document.getElementById('drag')
    var small = document.getElementById('smallBox')
    var big = document.getElementById('bigBox')
    var bigImg = document.getElementById('bigImg')

    //鼠标划入事件
    small.onmouseover = function () {
      drag.style.display = 'block'
      big.style.display = 'block'
    }
    //鼠标划出事件
    small.onmouseout = function () {
      drag.style.display = 'none'
      big.style.display = 'none'
    }
    //鼠标滑动的事件
    small.onmousemove = function (e) {
      var smallLeft = e.clientX - drag.offsetWidth / 2
      var smallTop = e.clientY - drag.offsetHeight / 2
      console.log(smallLeft)
      drag.style.left = smallLeft + 'px'
      drag.style.top = smallTop + 'px'
      if (drag.offsetLeft <= 0) {
        drag.style.left = 0
      }
      if (drag.offsetTop <= 0) {
        drag.style.top = 0
      }
      //最大距离
      var xLeft = small.offsetWidth - drag.offsetWidth
      var xTop = small.offsetHeight - drag.offsetHeight
      if (drag.offsetLeft > xLeft) {
        drag.style.left = xLeft + 'px'
      }
      if (drag.offsetTop > xTop) {
        drag.style.top = xTop + 'px'
      }
      //比例
      var m = drag.offsetLeft / xLeft
      var n = drag.offsetTop / xTop

      //右侧可以移动的最大距离
      var zLeft = bigImg.offsetWidth - big.offsetWidth
      var zTop = bigImg.offsetHeight - big.offsetHeight

      bigImg.style.left = -zLeft * m + 'px'
      bigImg.style.top = -zTop * n + 'px'
    }
  </script>
</body>

</html>