JavaScript

　　‍

onclick='return confirm("能力有限，敬请期待！");'

alert("hello js")
parseInt //把数值转为int
prompt("1","2") //弹出对话输入框，“2”为输入框的值
document.write() //在页面显示的内容

　　成绩

let score = prompt("请输入成绩：");
        let grade;
        switch (true) {
            case (score >= 90 && score <= 100):
                grade = "优";
                break;
            case (score >= 80 && score < 90):
                grade = "良";
                break;
            case (score >= 70 && score < 80):
                grade = "中";
                break;
            case (score >= 60 && score < 70):
                grade = "及格";
                break;
            default:
                grade = "不及格";
        }
        document.write("<h2>成绩评定</h2>你的成绩评定为："+grade);