三、选择和分组

1、| 选择 ( )分组

<script>
        //  | 选择      ()分组
        var str = "你去哪里，他在..."
        var reg = /你去|他在/g;
        console.log(str.replace(reg,"*"))  //*哪里，*...
    </script>

2、var reg = /^…..$/ 严格匹配 整个字符串必须满足正则

<script>
        var phone = "02788667777"
        var reg = /(027)?8\d{7}/;
                var reg = /^(027)?8\d{7}$/;   //严格匹配
        console.log(reg.test(phone))
    </script>