原生js拖拽元素(onmouseup不能够触发的原因)

<div class="box" id="drag"></div>

<script type="text/javascript">
window.onload = function(){
  var drag = document.getElementById('drag');
  // //点击某物体时，用drag对象即可，move和up是全局区域，
  // 也就是整个文档通用，应该使用document对象而不是drag对象(否则，采用drag对象时物体只能往右方或下方移动)  
  // 按下
  drag.onmousedown = function(event){
    console.log("drag按下的时候触发 " , )
    var event = event || window.event;  //兼容IE浏览器
    //    鼠标点击物体那一刻相对于物体左侧边框的距离=点击时的位置相对于浏览器最左边的距离-物体左边框相对于浏览器最左边的距离
           var diffX = event.clientX - drag.offsetLeft;
           var diffY = event.clientY - drag.offsetTop;
           if(typeof drag.setCapture !== 'undefined'){
        drag.setCapture(); 
           }
    // 移动
    document.onmousemove = function(event){
      var event = event || window.event;
      var moveX = event.clientX - diffX;
      var moveY = event.clientY - diffY;
      if(moveX < 0){
        moveX = 0
      }else if(moveX > window.innerWidth - drag.offsetWidth){
        moveX = window.innerWidth - drag.offsetWidth
      }
      if(moveY < 0){
        moveY = 0
      }else if(moveY > window.innerHeight - drag.offsetHeight){
        moveY =  window.innerHeight - drag.offsetHeight
      }
      drag.style.left = moveX + 'px';
      drag.style.top = moveY + 'px'
    }
    // 抬起停止移动
    document.onmouseup = function(event){
      console.log(  "抬起停止移动" )
      this.onmouseup = null;
      this.onmousemove = null;
       //修复低版本ie bug  
      if(typeof drag.releaseCapture!='undefined'){  
         drag.releaseCapture();  
      }  
    }
    // 解决有些时候,在鼠标松开的时候,元素仍然可以拖动;
    document.ondragstart = function(ev) {
      ev.preventDefault();
      console.log(1212)
    };
    document.ondragend = function(ev) {
      ev.preventDefault();
      console.log("asd")
    };
  }
}
</script>

Vue.prototype.dragandDrop=function(ele){
            var drag = document.getElementById(ele);
            // //点击某物体时，用drag对象即可，move和up是全局区域，
            // 也就是整个文档通用，应该使用document对象而不是drag对象(否则，采用drag对象时物体只能往右方或下方移动)  
            drag.onmousedown = function(event){
                var event = event || window.event;  //兼容IE浏览器
                //鼠标点击物体那一刻相对于物体左侧边框的距离=点击时的位置相对于浏览器最左边的距离-物体左边框相对于浏览器最左边的距离
                var diffX = event.clientX - drag.offsetLeft;
                var diffY = event.clientY - drag.offsetTop;
                if(typeof drag.setCapture !== 'undefined'){
                        drag.setCapture(); 
                }
                if(event.stopPropagation) event.stopPropagation();
                if(event.preventDefault) event.preventDefault();
                document.onmousemove = function(event){
                    var event = event || window.event;
                    var moveX = event.clientX - diffX;
                    var moveY = event.clientY - diffY;
                    if(moveX < 0){
                        moveX = 0
                    }else if(moveX > window.innerWidth - drag.offsetWidth){
                        moveX = window.innerWidth - drag.offsetWidth
                    }
                    if(moveY < 0){
                        moveY = 0
                    }else if(moveY > window.innerHeight - drag.offsetHeight){
                        moveY =  window.innerHeight - drag.offsetHeight
                    }
                    drag.style.left = moveX + 'px';
                    drag.style.top = moveY + 'px'
                }
            }
        }
        // 抬起方法(拖拽停止)
        Vue.prototype.stop=function(ele){
            console.log(11);
            document.onmouseup = function(event){
                var event = event || window.event;  //兼容IE浏览器
                if(event.stopPropagation) event.stopPropagation();//这个可以删除
                if(event.preventDefault) event.preventDefault();//这个可以删除
                console.log( " this.onmousemove", this.onmousemove);
                this.onmousemove = null;
                this.onmouseup = null;
            }
        }

<rich-text class="rich-text-com"   id="richdragIndex"  @aaa="down"  @bbb="upuo"></rich-text>
<script>
// 解决有些时候,在鼠标松开的时候,元素仍然可以拖动;
document.ondragstart = function(ev) {
    ev.preventDefault();
};
document.ondragend = function(ev) {
    ev.preventDefault();
};
 export default {
     data(){
            return{
            }
    },
     methods:{
            down(){
                console.log("ppp");
                this.dragandDrop("richdragIndex");
            },
            upuo(){
                console.log("触发抬起");
                this.stop("richdragIndex")
            }
      }
 }