{bind:function (el,binding) {
    let oDiv = el;  //当前元素
    let self = this; //上下文
    oDiv.onmousedown = function (e) {
     //鼠标按下，计算当前元素距离可视区的距离
      let disX = e.clientX - oDiv.offsetLeft;
      let disY = e.clientY - oDiv.offsetTop;
      document.onmousemove = function (e) {
       //通过事件委托，计算移动的距离 
        let l = e.clientX - disX;
        let t = e.clientY - disY;
       //移动当前元素 
        oDiv.style.left = l + 'px';
        oDiv.style.top = t + '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;
       };
    };
  }
}

);
window.onload = function () {
let vm = new Vue({
el: '#Box',data: {
val: '123',style: {
width: '100px',height: '100px',background: 'aqua',position: 'absolute',right: '30px',top: 0
}
},methods:{
//接受传来的位置数据，并将数据绑定给data下的val
greet(val){
vm.val = val;
}
},});
}