g 全局捕获，捕获完前边的，再次输入捕获后边的
i 忽略大小写
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head>
<body><script>var datestr = "time 2025-01-02 12.20.20 to 2099-01-02 12.20.20"var regg = /\d{4}-\d{1,2}-\d{1,2}/gvar newdatastr1 = regg.exec(datestr)console.log(newdatastr1[0].split("-").join("/"))var newdatastr2 = regg.exec(datestr)console.log(newdatastr2[0].split("-").join("/"))//i 忽略大小写var aa = /[a-z]/iconsole.log(aa.test("aa"))console.log(aa.exec("AA"))</script>
</body>
</html>