vue中的随机验证码

<div class="yzmInput">
    <el-input placeholder="请输入图形验证码" v-model="yzmcode" maxlength="4" @keyup.enter.native="LoginBtn">
    　　<i slot="prefix" class="el-input__icon el-icon-key"></i>
    </el-input>
 </div>
 <div class="yzm" @click="changeYzmCode">
     <div>{{ imgCode }}</div>
 </div>

.yzmInput {
        width: 250px;
        height: 100%;
        display: flex;
        flex-direction: row;
        align-items: center;
}
.yzm {
        width: 82px;
        height: 40px;
        display: flex;
        flex-direction: row;
        justify-content: center;
        align-items: center;
        background: url("../assets/login/yzm.png") no-repeat center center;
        background-size: 100% 100%;
        div {
          transform: skew(-40deg);
        }
 }

// 随机验证码
changeYzmCode() {
    var code = "";
    var codeLength = 4; // 验证码的长度
    var random = new Array(0,1,2,3,4,5,6,7,8,9,
                "A","B","C","D","E","F","G","H","I","J","K","L",
                "M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"); // 随机数
    for (let i = 0; i < codeLength; i++) {
        // 循环操作
        let index = Math.floor(Math.random() * 36); // 取得随机数的索引（0~35）
        code += random[index]; // 根据索引取得随机数加到code上
    }
    this.imgCode = code; //把code值赋给验证码
},