鼠标拖拽移动DIV 记录一下

  export default {
    data() {
      return {}
    },
    methods: {
      mousedown(e) {
        // 被移动的主体 mainDiv
        const mainDiv = document.querySelector('.vvhan-com')
        // 鼠标点击位置与主体边的距离
        const distanceX = e.clientX - mainDiv.offsetLeft
        const distanceY = e.clientY - mainDiv.offsetTop
        // 鼠标移动事件
        document.onmousemove = function (ev) {
          const _e = ev || e
          //移动时，鼠标距离当前窗口x轴坐标 - 鼠标在拖拽元素的坐标 = 剩下距离body的x轴坐标
          //将这个数值设置为拖拽元素的left、top
          let boxLeft = _e.clientX - distanceX;
          let boxTop = _e.clientY - distanceY;
          //获取body的页面可视宽高
          const clientHeight = document.documentElement.clientHeight || document.body.clientHeight
          const clientWidth = document.documentElement.clientWidth || document.body.clientWidth
          //限制拖拽宽高
          boxLeft = boxLeft < 0 ? 0 : boxLeft > clientWidth - mainDiv.offsetWidth ? clientWidth - mainDiv
            .offsetWidth : boxLeft
          boxTop = boxTop < 0 ? 0 : boxTop > clientHeight - mainDiv.offsetHeight ? clientHeight - mainDiv
            .offsetHeight : boxTop

          mainDiv.style.top = boxTop + 'px'
          mainDiv.style.left = boxLeft + 'px'
        }
        // 鼠标松开事件 结束拖拽
        document.onmouseup = function () {
          document.onmousemove = null
          document.onmouseup = null
        }
      }
    }
  }




  body {
    position: relative !important;
    background: url('https://static.4ce.cn/ipfs/QmQtvCE2DMkYJKWicdaJxh3Vh47ca6t25RxBGrbre5Cy2p');
    background-size: cover;
    padding: 0;
    margin: 0;
  }




  .vvhan-com {
    user-select: none;
    position: absolute !important;
    box-sizing: border-box;
    padding: 6px;
    top: 36px;
    right: 36px;
    box-shadow: 0 2px 12px 0 rgba(0, 0, 0, .1);
    background-color: rgba(255, 255, 255, 0.2);
    width: 340px;
    z-index: 9;
    font-size: 14px;

    .title {
      margin-bottom: 6px;
      font-size: 16px;
      line-height: 28px;
      border-bottom: 1px rgba(0, 0, 0, .1) solid;
      cursor: move;
    }

    h1 {
      color: #000;
    }
  }