vue elemenet 弹窗拖拽

1、在main.js同级建一个文件directives.js

import Vue from 'vue';

// v-dialogDrag: 弹窗拖拽
Vue.directive('dialogDrag', {
  bind(el, binding, vnode, oldVnode) {
    const dialogHeaderEl = el.querySelector('.el-dialog__header');
    const dragDom = el.querySelector('.el-dialog');
    dialogHeaderEl.style.cursor = 'move';

    // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
    const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null);

    dialogHeaderEl.onmousedown = (e) => {
      // 鼠标按下，计算当前元素距离可视区的距离
      const disX = e.clientX - dialogHeaderEl.offsetLeft;
      const disY = e.clientY - dialogHeaderEl.offsetTop;

      // 获取到的值带px 正则匹配替换
      let styL, styT;

      // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px
      if (sty.left.includes('%')) {
        styL = +document.body.clientWidth * (+sty.left.replace(/\%/g, '') / 100);
        styT = +document.body.clientHeight * (+sty.top.replace(/\%/g, '') / 100);
      } else {
        styL = +sty.left.replace(/\px/g, '');
        styT = +sty.top.replace(/\px/g, '');
      };

      document.onmousemove = function (e) {
        // 通过事件委托，计算移动的距离
        const l = e.clientX - disX;
        const t = e.clientY - disY;

        // 移动当前元素
        dragDom.style.left = `${l + styL}px`;
        dragDom.style.top = `${t + styT}px`;

        //将此时的位置传出去
        //binding.value({x:e.pageX,y:e.pageY})
      };

      document.onmouseup = function (e) {
        document.onmousemove = null;
        document.onmouseup = null;
      };
    }
  }
})

// v-dialogDragWidth: 弹窗宽度拖大 拖小
Vue.directive('dialogDragWidth', {
  bind(el, binding, vnode, oldVnode) {
    const dragDom = binding.value.$el.querySelector('.el-dialog');

    el.onmousedown = (e) => {

      // 鼠标按下，计算当前元素距离可视区的距离
      const disX = e.clientX - el.offsetLeft;

      document.onmousemove = function (e) {
        e.preventDefault(); // 移动时禁用默认事件

        // 通过事件委托，计算移动的距离
        const l = e.clientX - disX;
        dragDom.style.width = `${l}px`;
      };

      document.onmouseup = function (e) {
        document.onmousemove = null;
        document.onmouseup = null;
      };
    }
  }
})

2、main.js添加引用

import './directives.js'

3、在需要用到拖拽功能的弹窗标签上加 

v-dialogDrag

例如：

<el-dialog title="预览" :visible.sync="viewDialogVisible"  v-dialogDrag>
</el-dialog>

即可