vue3.0+element plus 的el-container中，el-aside可以拖拽的方法（drag）

首先在setup中定义一个类

 const widthData=reactive({
      with:500
    });

然后编写方法：

    const updateWidth=()=>{
        
           let resize= document.getElementById("asideId");
           console.log(resize);
resize.onmousedown = function(e) {
        // resize.style.background = "#818181";
        let startX = e.clientX;
        // resize.left = resize.offsetLeft;
        document.onmousemove = function(e) {
        
          let endX = e.clientX;
          let moveLen = endX - startX;
          startX = endX;
           widthData.with += moveLen;
        };
        document.onmouseup = function() {
          // 颜色恢复
          resize.style.background = "";
          document.onmousemove = null;
          document.onmouseup = null;
        };
        return false;
      };

      }

然后在onMounted中调用方法

最后在el-aside中加入id="asideId"  :width="widthData.with+'px'" 绑定即可