正则表达式（轻松入门级）

// 通过构造函数的方式
　　var oReg = new RegExp('study', 'i');

// 通过语法糖（简写）的形式
 　var oReg = /study/i;

　　// 首先我来看test
　　//我们要在字符串str中找出符合Reg的规则的子字符串，符合则返回true，不符合则返回false
    var str = 'Good good study, Day day up! Good good study';
    var Reg1= /good/ig;
    var Reg2= /goood/ig;
    console.log(Reg1.test(str));//true
    console.log(Reg2.test(str));//false

    // 接下来我们再来看 exec
    //用于检索字符串中的正则表达式的匹配。返回一个数组，其中存放匹配的结果，如果未找到匹配，则返回值为null
    var str = 'Good good study, Day day up! Good good study';
    var Reg= /good/ig;
    console.log(Reg.exec(str));//["Good", index: 0, input: "Good good study, Day day up! Good good study"]
    console.log(Reg.exec(str));//["good", index: 5, input: "Good good study, Day day up! Good good study"]
    console.log(Reg.exec(str));//["Good", index: 29, input: "Good good study, Day day up! Good good study"]
    console.log(Reg.exec(str));//["good", index: 34, input: "Good good study, Day day up! Good good study"]
    console.log(Reg.exec(str));//null
    //注：如果没有指定g修饰符，那么每次匹配都是从头开始匹配，如果指定g修饰符以后，下次匹配则从上次匹配的结束位置开始匹配。

　
　　　var str = 'Good good study, Day day up! Good good study';
     var Reg= /study/ig;
     console.log(str.search(Reg));//10
     console.log(str.match(Reg));// ["study", "study"]
     console.log(str.replace(Reg,'aaaa'));//Good good aaaa, Day day up! Good good aaaa
     console.log(str.split(Reg));//["Good good ", ", Day day up! Good good ", ""]

var str ='gd god good goood gooood';

     var Reg1 =/go*d/ig; //*：匹配前面的子表达式零次或多次
     console.log(str.match(Reg1));//["gd", "god", "good", "goood", "gooood"]


     var Reg2 =/go+d/ig; //+：匹配前面的子表达式一次或多次
     console.log(str.match(Reg2));//["god", "good", "goood", "gooood"]


     var Reg3 =/go?d/ig; //？：匹配前面的子表达式零次或一次
     console.log(str.match(Reg3));//["gd", "god"]


     var Reg4 =/go{2}d/ig; //{n}：匹配确定n次
     console.log(str.match(Reg4));//["good"]


     var Reg5 =/go{2,}d/ig; //{n,}：至少匹配n次
     console.log(str.match(Reg5));//["good", "goood", "gooood"]
     

     var Reg6 =/go{1,3}d/ig; //{n, m}：最少匹配n次且最多匹配m次
     console.log(str.match(Reg6));//["god", "good", "goood"]

     var str = 'aiod acd abd add aed afd ahd $%#@ 12345678 asdfghh';

     var Reg1 = /a[abc]d/ig;        //[xyz]：字符集合。匹配所包含的任意一个字符
     console.log(str.match(Reg1)); //["acd", "abd"]

     var Reg2 = /a[^abc]d/ig;       //[^xyz]：负值字符集合。匹配未包含的任意字符
     console.log(str.match(Reg2)); // ["add", "aed", "afd", "ahd", "asd"]

     var Reg3 = /a[a-z]d/ig;        //[a-z]：字符范围。匹配指定范围内的任意字符
     console.log(str.match(Reg3)); //["acd", "abd", "add", "aed", "afd", "ahd", "asd"]

     var Reg4 = /a[^a-e]d/ig;      //[^a-z]：负值字符范围。匹配任何不在指定范围内的任意字符
     console.log(str.match(Reg4)); //["afd", "ahd", "asd"]

     var Reg5 = /\d+/ig;             //  \d：匹配一个数字字符。
     console.log(str.match(Reg5));  //["12345678"]

     var Reg6 = /\D+/ig;            //    \D：匹配一个非数字字符
     console.log(str.match(Reg6));  //["aiod acd abd add aed afd ahd $%#@ ", " asdfghh"]

     var Reg7 = /\w+/ig;            //   \w：匹配包含数字,字母,下划线的任何单词字符,等价于[a-z0-9A-Z_]
     console.log(str.match(Reg7));  //["aiod", "acd", "abd", "add", "aed", "afd", "ahd", "12345678", "asdfghh"]

     var Reg8 = /\W+/ig;            //    \W：匹配任何非单词字符。等价于[^a-z0-9A-Z_]
     console.log(str.match(Reg8));  // [" ", " ", " ", " ", " ", " ", " $%#@ ", " "]

     var Reg9 = /\s+/ig;            //    \s：匹配任何空白字符
     console.log(str.match(Reg9));  //[" ", " ", " ", " ", " ", " ", " ", " ", " "]

     var Reg10 = /\S+/ig;            //    \S：匹配任何非空白字符
     console.log(str.match(Reg10)); //["aiod", "acd", "abd", "add", "aed", "afd", "ahd", "$%#@", "12345678", "asdfghh"]

// ^：匹配输入字符串的开始位置。
    var str  ='123456';  
    var Reg1  =/^\d+/ig;
    var Reg2  =/\d/ig;
    console.log(Reg1.test(str));//true

//$：匹配输入字符串的结束位置。
    var str ='abcd789';
    var Reg =/.+\d{3}$/ig;
    console.log(Reg.test(str));//true

// \b：限定单词以什么开头和结尾，\B：限定单位不以什么开头和结尾
var str = 'good ogoodm goods sgoods';

var reg1 = /\bg\w+/g;
var reg2 = /\w+d\b/g;
console.log(str.match(reg1));//["good", "goods"]
console.log(str.match(reg2));//["good"]
var reg3 = /\Bg\w+/g;
var reg4 = /\w+d\B/g;
console.log(str.match(reg3));//["goodm", "goods"]
console.log(str.match(reg4));//["ogood", "good", "sgood"]

 // 特殊字符：. + * ? {} [] ^ $ \

    var str = '++++++-*/%';
    var oReg = /\++/g;
    console.log(str.match(oReg));//["++++++"]

// 选择匹配符
var str = 'gooqd gaawd gwwsd';
var oReg = /g(ooq|aaw)d/g;
console.log(str.match(oReg));// ["gooqd", "gaawd"]

// 下面是国内 13、15、18开头的手机号正则表达式。（可根据目前国内收集号扩展前两位开头号码）
var reg = /^(13[0-9]|14[5|7]|15[0|1|2|3|5|6|7|8|9]|18[0|1|2|3|5|6|7|8|9])\\d{8}$/

//字符串只能是中文
var oReg = /^[\u2E80-\u9FFF]+$/;

// 18位身份证检测
 var oReg = /^\d{17}[\dxX]$/;

//日期检测
 var oReg = /^\d{4}(\-|\/)\d{1,2}\1\d{1,2}$/;

// 去除首尾的空格
var sVal = oSpace.value;
var oReg = /^\s+(\S*)\s+$/;
console.log(sVal.replace(oReg, '$1'));

//检测文件格式
var oReg = /.+\.(jpg|jpeg|png|gif)$/i;

//检测邮编
var oReg = /^\d{6}$/;

// 过滤
var str = '小明说小强是混蛋，小强说他不是混蛋';
str.replace(/混蛋/g, '**');