实现div宽度拖动

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

<script>

    export default {
        name: 'App',
        components: {},
        methods:{
            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 () {
                            //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;
                    };
                }
            },
        },
        mounted(){
            this.dragControllerDiv();
        }
    }
</script>

<style>
    /* 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);
    }
</style>