Vue实现拖拽

<template>
    <!--绑定按下事件-->
    <div id="app" @mousedown="move">
        {{positionX}}
        {{positionY}}
    </div>
</template>

<script>
export default {
  name: 'App',
  data(){
    return {
      positionX:0,
      positionY:0
    }
  },
    methods:{
        move(e){
            let odiv = e.target;        //获取目标元素
            
            //算出鼠标相对元素的位置
            let disX = e.clientX - odiv.offsetLeft;
            let disY = e.clientY - odiv.offsetTop;
            document.onmousemove = (e)=>{       //鼠标按下并移动的事件
                //用鼠标的位置减去鼠标相对元素的位置，得到元素的位置
                let left = e.clientX - disX;    
                let top = e.clientY - disY;
                
                //绑定元素位置到positionX和positionY上面
                this.positionX = top;
                this.positionY = left;
                
                //移动当前元素
                odiv.style.left = left + 'px';
                odiv.style.top = top + 'px';
            };
            document.onmouseup = (e) => {
                document.onmousemove = null;
                document.onmouseup = null;
            };
        }
    }
}
</script>

<style>
    #app{
        position: relative;     /*定位*/
        top: 10px;
        left: 10px;
        width: 200px;
        height: 200px;
        background: #ec1a1a;
    }
</style>

 如果报错e is defined but no used 

解决:更改package.json的rules

    "rules": {
      "no-unused-vars": "off"
    }