js生成随机验证码

html代码
 <div class="flex aic ">
          <div class="in_boc2 flex aic ">
                <i class="iconfont ml-10 icon-yanzhengma1"></i>
                <input type="text" placeholder="请输入验证码" id="codeInput" class="keycode1">
            </div>
            <div class="text-wrapper_27 mt-10">
                <div id="code" class="text_53" onclick="displayRandomCode()"> </div>
            </div> 
     </div>


// 生成随机验证码
function generateRandomCode(length) {
    var charset = "0123456789";
    var code = "";
    for (var i = 0; i < length; i++) {
        var randomIndex = Math.floor(Math.random() * charset.length);
        code += charset[randomIndex];
    }
    return code;
}
var inputCode = null;
// 显示验证码
function displayRandomCode() {
    var codeElement = document.getElementById("code");
    var code = generateRandomCode(4); // 生成长度为 4 的验证码
    codeElement.textContent = code;
    inputCode = code;
}
window.addEventListener("load", function () {
    displayRandomCode();
});




//判断逻辑
var yzm = $("#codeInput").val();;
    if (yzm == null || yzm == '' || inputCode == null || inputCode == '') {
        layer.msg('请输入验证码！');
        return;
    }
    if (yzm != inputCode) {
        layer.msg('验证码错误，请重新输入！');
        return;
    }
//其他逻辑