基于JavaScript实现拖动滑块效果

本文实例为大家分享了js拖动滑块效果的具体代码，供大家参考，具体内容如下
效果：
代码：
<!DOCTYPE html>
<html lang="zh-cn">

 <head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />
  <title>鼠标拖动小方块</title>
  <style type="text/css">
   .lineDiv {
    position: relative;
    height: 5px;
    background: red;
    width: 300px;
    margin: 50px auto;
   }

   .lineDiv .minDiv {
    position: absolute;
    top: -5px;
    left: 0;
    width: 15px;
    height: 15px;
    background: green;
    cursor: pointer
   }

   .lineDiv .minDiv .vals {
    position: absolute;
    font-size: 20px;
    top: -45px;
    left: -10px;
    width: 35px;
    height: 35px;
    line-height: 35px;
    text-align: center;
    background: blue;
   }

   .lineDiv .minDiv .vals:after {
    content: "";
    width: 0px;
    height: 0px;
    border-top: 6px solid blue;
    border-left: 6px solid transparent;
    border-right: 6px solid transparent;
    border-bottom: 6px solid transparent;
    display: block;
    margin-left: 11px;
   }
  </style>
 </head>

 <body>
  <center>
   <h3>用鼠标拖动小方块<span id="msg">0</span>%</h3>
  </center>
  <div id="lineDiv" class="lineDiv">
   <div id="minDiv" class="minDiv">
    <div id="vals" class="vals">0</div>
   </div>
  </div>
  <script>
   window.onload = function() {

    var lineDiv = document.getElementById('lineDiv'); //长线条
    var minDiv = document.getElementById('minDiv'); //小方块
    var msg = document.getElementById("msg");
    var vals = document.getElementById("vals");
    var ifBool = false; //判断鼠标是否按下

    //鼠标按下方块
    minDiv.addEventListener("touchstart", function(e) {
     e.stopPropagation();
     ifBool = true;
     console.log("鼠标按下")
    });

    //拖动
    window.addEventListener("touchmove", function(e) {
     console.log("鼠标拖动")
     if(ifBool) {
      var x = e.touches[0].pageX || e.touches[0].clientX; //鼠标横坐标var x
      var lineDiv_left = getPosition(lineDiv).left; //长线条的横坐标
      var minDiv_left = x - lineDiv_left; //小方块相对于父元素（长线条）的left值 
      if(minDiv_left >= lineDiv.offsetWidth - 15) {
       minDiv_left = lineDiv.offsetWidth - 15;
      }
      if(minDiv_left < 0) {
       minDiv_left = 0;
      }
      //设置拖动后小方块的left值
      minDiv.style.left = minDiv_left + "px";
      msg.innerText = parseInt((minDiv_left / (lineDiv.offsetWidth - 15)) * 100);
      vals.innerText = parseInt((minDiv_left / (lineDiv.offsetWidth - 15)) * 100);
     }
    });
    //鼠标松开
    window.addEventListener("touchend", function(e) {
     console.log("鼠标弹起")
     ifBool = false;
    });
    //获取元素的绝对位置
    function getPosition(node) {
     var left = node.offsetLeft; //获取元素相对于其父元素的left值var left
     var top = node.offsetTop;
     current = node.offsetParent; // 取得元素的offsetParent
     　 // 一直循环直到根元素
     　　
     while(current != null) {　　
      left += current.offsetLeft;　　
      top += current.offsetTop;　　
      current = current.offsetParent;　　
     }
     return {
      "left": left,
      "top": top
     };
    }
   }
  </script>
 </body>

</html>
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基于JavaScript实现拖动滑块效果

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