请老师检查代码的合理性和规范性，谢谢

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>闪烁的文字</title>
        <style type="text/css">
            div{
                width:200px;
                height:200px;
                line-height:200px;
                border:2px solid gray;
                text-align:center;
                color:red;
            }
        </style>
    </head>
<body>
    <h3>会闪烁的文字</h3>
        <div id="text"> </div>
        <script type="text/javascript">
            var objDiv = document.getElementById("text");
            objDiv.innerHTML="☆☆☆今日特卖☆☆☆";
            var flag=true;
            window.setInterval(function(){
                if (flag) {
                    objDiv.innerHTML="★★★今日特卖★★★";
                }else{
                    objDiv.innerHTML="☆☆☆今日特卖☆☆☆";
                }
                flag = !flag;
            },500);
        </script>
    </body>
</html>

wangstudyvc 2019-08-26

源自：JS BOM基础 1-25 编程练习