OK不OK老师

来源：3-29 编程练习

2022一定转行成功

2021-02-28 14:36:15

相关代码：

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>toUpperCase和toLowerCase</title>
</head>
<body>
<script>
    var str="Never deter till tomorrow that which you can do today";
var index=str.indexOf("tomorrow");//补充代码
var strNew=str.substr(index,8);//补充代码
var upperStr=str.replace("tomorrow",strNew.toUpperCase());//补充代码
document.write(upperStr);
</script>
</body>
</html>