9-3量词

 <script>
        /*
        规定字符出行的次数
        正则  test（）
        */
        var reg = /[0-9]{6}/
        var pwd = 1234576;
        var t = reg.test(pwd);
        console.log(t)
    </script>

<!-- 
        {m} 就出行m次
        {m,}至少出行m次
        {m,n}
     -->
    <script>
        var str = "2123jhfdd"
        var reg = /\d{6,}/;
        console.log(reg.test(str))
    </script>

<!-- 
        {3,}
        {3}
        {3,6}
        ?{0,1}
        +{1,}
        *{0,}
     -->
     <script>
         var str = "hello123";
         var reg = /[a-z]+/;
         console.log(str.replace(reg,"*"))
         console.log(str.replace(/[a-z]*/,"*"))
     </script>

贪婪和懒惰

  <script>
        // 贪婪模式：在给定量词的情况下，会取最大的量词
        var str = "1231231hello";
        var reg = /\d{3,6}/;
        console.log(str.replace(reg,"*"))
        //test 只要正则表达式的某一段满足，就输出结果为true
        console.log(reg.test(str))
        // tips:+,*默认就是贪婪模式
    </script>

懒惰模式

 <script>
        //懒惰模式
        var str = "123123hello";
        var reg = /\d{3,6}?/;
        console.log(str.replace(reg,"*"))
    </script>

选择和分组

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

 <script>
        var url = "http://www.baidu.com";
        var https = "https:www.daidu.com"
        var reg = /(http|https):\/\/www\baidu\.com/;
        console.log(reg.test(url))
        console.log(reg.test(https))
    </script>

  <script>
        var phone = "02788667777";
        //^    后面一个$ 严格匹配的意思必须满足正则条件
        var reg = /^(027)?8\d{7}$/;
        console.log(reg.test(phone))
    </script>

 <input type="text" id="app">
    <script>
        //(086)?1[356789]\d{9}$
       var reg = /^(086)?1[3-9]\d{9}$/;
       $("#app").keyup(function(event){
           if(event.keyCode ==13){
               var value = $(this).val();
               console.log(reg.test(value))
           }
       })
    </script>