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JS滾輪控制圖片縮放大小和拖動的實(shí)例代碼

更新時間：2018年11月20日 08:37:36 作者：小角色Byme

本文通過實(shí)例代碼給大家介紹了js 滾輪控制圖片縮放大小和拖動，代碼簡單易懂，非常不錯，具有一定的參考借鑒價值 ,需要的朋友可以參考下

具體代碼如下所示：

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
  <style>
  .dragAble {
    position: relative;
    cursor: move;
  }
  .img-con {
    position: relative;
    width: 713px;
    height: 455px;
    overflow: hidden;
    border: 1px solid red;
  }
  </style>
</head>
<body>
  <p class="img-con"><img src="http://img03.tooopen.com/uploadfile/downs/images/20110714/sy_20110714135215645030.jpg" class="dragAble" /></p>
  <script type="text/javascript" charset="utf-8">
  window.onload = function() {
      var oImg = document.getElementsByTagName("img")[0];
      function fnWheel(obj, fncc) {
        obj.onmousewheel = fn;
        if (obj.addEventListener) {
          obj.addEventListener('DOMMouseScroll', fn, false);
        }
        function fn(ev) {
          var oEvent = ev || window.event;
          var down = true;
          if (oEvent.detail) {
            down = oEvent.detail > 0
          } else {
            down = oEvent.wheelDelta < 0
          }
          if (fncc) {
            fncc.call(this, down, oEvent);
          }
          if (oEvent.preventDefault) {
            oEvent.preventDefault();
          }
          return false;
        }
      };
      fnWheel(oImg, function(down, oEvent) {
        var oldWidth = this.offsetWidth;
        var oldHeight = this.offsetHeight;
        var oldLeft = this.offsetLeft;
        var oldTop = this.offsetTop;
        var scaleX = (oEvent.clientX - oldLeft) / oldWidth; //比例
        var scaleY = (oEvent.clientY - oldTop) / oldHeight;
        if (down) {
          this.style.width = this.offsetWidth * 0.9 + "px";
          this.style.height = this.offsetHeight * 0.9 + "px";
        } else {
          this.style.width = this.offsetWidth * 1.1 + "px";
          this.style.height = this.offsetHeight * 1.1 + "px";
        }
        var newWidth = this.offsetWidth;
        var newHeight = this.offsetHeight;
        this.style.left = oldLeft - scaleX * (newWidth - oldWidth) + "px";
        this.style.top = oldTop - scaleY * (newHeight - oldHeight) + "px";
      });
    }
    <!--
    //拖拽
  var ie = document.all;
  var nn6 = document.getElementByIdx && !document.all;
  var isdrag = false;
  var y, x;
  var oDragObj;
  function moveMouse(e) {
    if (isdrag) {
      oDragObj.style.top = (nn6 ? nTY + e.clientY - y : nTY + event.clientY - y) + "px";
      oDragObj.style.left = (nn6 ? nTX + e.clientX - x : nTX + event.clientX - x) + "px";
      return false;
    }
  }
  function initDrag(e) {
    var oDragHandle = nn6 ? e.target : event.srcElement;
    var topElement = "HTML";
    while (oDragHandle.tagName != topElement && oDragHandle.className != "dragAble") {
      oDragHandle = nn6 ? oDragHandle.parentNode : oDragHandle.parentElement;
    }
    if (oDragHandle.className == "dragAble") {
      isdrag = true;
      oDragObj = oDragHandle;
      nTY = parseInt(oDragObj.style.top + 0);
      y = nn6 ? e.clientY : event.clientY;
      nTX = parseInt(oDragObj.style.left + 0);
      x = nn6 ? e.clientX : event.clientX;
      document.onmousemove = moveMouse;
      return false;
    }
  }
  document.onmousedown = initDrag;
  document.onmouseup = new Function("isdrag=false");
  </script>
</body>
</html>

只縮放

<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<img border="0" src="http://img03.tooopen.com/uploadfile/downs/images/20110714/sy_20110714135215645030.jpg" onmousewheel="return rollImg(this)">
</body>
<script language="javascript">
function rollImg(o){
  /* 獲取當(dāng)前頁面的縮放比
    若未設(shè)置zoom縮放比，則為默認(rèn)100%，即1，原圖大小
  */ 
  var zoom=parseInt(o.style.zoom)||100;
  /* event.wheelDelta 獲取滾輪滾動值并將滾動值疊加給縮放比zoom
    wheelDelta統(tǒng)一為±120，其中正數(shù)表示為向上滾動，負(fù)數(shù)表示向下滾動
  */
  zoom+=event.wheelDelta/12;
  /* 如果縮放比大于0，則將縮放比加載到頁面元素 */
  if (zoom>0) o.style.zoom=zoom+'%';
  /* 如果縮放比不大于0，則返回false，不執(zhí)行操作 */
  return false;
}
</script>
</html>

總結(jié)

以上所述是小編給大家介紹的JS滾輪控制圖片縮放大小和拖動的實(shí)例代碼，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復(fù)大家的。在此也非常感謝大家對腳本之家網(wǎng)站的支持！

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