<div class="box" ref="box">
   <div class="left">
    <!--左侧div内容-->
   </div>
   <div class="resize" title="收缩侧边栏">
    "mid">
    <!--右侧div内容-->
   </div>
  </div>

 /* 拖拽相关样式 */
 /*包围div样式*/
 .box {
  width: 100%;
  height: 100%;
  margin: 1% 0px;
  overflow: hidden;
  box-shadow: -1px 9px 10px 3px rgba(0, 0, 0, 0.11);
 }
 /*左侧div样式*/
 .left {
  width: calc(32% - 10px); /*左侧初始化宽度*/ 
  height: 100%;
  background: #FFFFFF;
  float: left;
 }
 /*拖拽区div样式*/
 .resize {
  cursor: col-resize;
  float: left;
  position: relative;
  top: 45%;
  background-color: #d6d6d6;
  border-radius: 5px;
  margin-top: -10px;
  width: 10px;
  height: 50px;
  background-size: cover;
  background-position: center;
  /*z-index: 99999;*/
  font-size: 32px;
  color: white;
 }
 /*拖拽区鼠标悬停样式*/
 .resize:hover {
  color: #444444;
 }
 /*右侧div'样式*/
 .mid {
  float: left;
  width: 68%; /*右侧初始化宽度*/
  height: 100%;
  background: #fff;
  box-shadow: -1px 4px 5px 3px rgba(0, 0, 0, 0.11);
 }

dragControllerDiv: function () {
    var resize = document.getElementsByClassName('resize');
    var left = document.getElementsByClassName('left');
    var mid = document.getElementsByClassName('mid');
    var box = document.getElementsByClassName('box');
    for (let i = 0; i < resize.length; i++) {
     // 鼠标按下事件
     resize[i].onmousedown = function (e) {
      //颜色改变提醒
      resize[i].style.background = '#818181';
      var startX = e.clientX;
      resize[i].left = resize[i].offsetLeft;
      // 鼠标拖动事件
      document.onmousemove = function (e) {
       var endX = e.clientX;
       var moveLen = resize[i].left + (endX - startX); // （endx-startx）=移动的距离。resize[i].left+移动的距离=左边区域最后的宽度
       var maxT = box[i].clientWidth - resize[i].offsetWidth; // 容器宽度 - 左边区域的宽度 = 右边区域的宽度

       if (moveLen < 32) moveLen = 32; // 左边区域的最小宽度为32px
       if (moveLen > maxT - 150) moveLen = maxT - 150; //右边区域最小宽度为150px

       resize[i].style.left = moveLen; // 设置左侧区域的宽度

       for (let j = 0; j < left.length; j++) {
        left[j].style.width = moveLen + 'px';
        mid[j].style.width = (box[i].clientWidth - moveLen - 10) + 'px';
       }
      };
      // 鼠标松开事件
      document.onmouseup = function (evt) {
       //颜色恢复
       resize[i].style.background = '#d6d6d6';
       document.onmousemove = null;
       document.onmouseup = null;
       resize[i].releaseCapture && resize[i].releaseCapture(); //当你不在需要继续获得鼠标消息就要应该调用ReleaseCapture()释放掉
      };
      resize[i].setCapture && resize[i].setCapture(); //该函数在属于当前线程的指定窗口里设置鼠标捕获
      return false;
     };
    }
   },

this.dragControllerDiv();