javascript-正则表达式

/*
var reg = /a/;
alert(reg);
*/

var reg = new RegExp("b");
alert(reg);

/*
var reg = /a/;
var str = "a";
alert(  reg.test(str) );   //true
alert(typeof reg.exec(str) );  //Object 删除typeof 返回a
*/
 var num1 = 1;
  // var reg1 = /"+num1+"/;  
 var reg1 = new RegExp(num1);
   var str1 = "1";
   //alert(reg1);//"+num1+"/
   alert( reg1.test(str1)  ); //true

/*var reg = /[abc]/; //匹配中括号内的任意一个字符
var str = "c";
alert(reg.test(str));  //true
*/


/*var reg1 = /[^abc]/;
var str1 = "u";
alert(reg1.test(str1)); //true
*/


/*var reg2 = /[3-9]/;
var num2 = 5;
alert(reg2.test(num2));//true
*/



//var reg3 = /[a-z]/;
/*var reg3 = /[A-Z]/;
var str3 = "A";
alert(reg3.test(str3)); //true
*/


//var reg4 = /[0-9a-zA-Z]/;  //数字  大小写字母

//var reg1 = /\d/;
/*
var reg1 = /\D/;
var num1 = 5;
alert( reg1.test(num1) );
*/


//var reg2 = /\w/;
/*var reg2 = /\W/;
var str2 = "_";
alert(reg2.test(str2));*/


//var reg3 = /\s/;
/*var reg3 = /\S/;
var str3 = " ";
alert( reg3.test(str3)  );*/

/*var reg4 = /\ba/;
var str4 = " a";
alert( reg4.test(str4)  );*/


/*
var reg5 = /./;
var str5 = "\n";
alert(  reg5.test(str5)  );
*/

var reg6 = /\./;  //.有特殊含义、除了换行符以外的任意字符
var str6 = ".";
alert( reg6.test(str6) );

/*
var reg = /\d/; //  \d ====>数字  没有限定符num中，只要有数字即可
var num = "5a";
alert(reg.test(num));
*/

/*
var reg1 = /\w/; //数字  字母   下划线
var str1 = "^_^";
alert(  reg1.test(str1) );
*/


/*var reg2 = /^\d\d$/;  // 以数字开始   以数字结束  ===》数字只有一位数
var num2 = "55";
alert( reg2.test(num2)  );*/

/*
var reg3 = /^\d{11}$/; // 手机号===>11位数
var num3 = 1234567890;
alert( reg3.test(num3) ); //false
*/


//匹配数字最少匹配到6次   , 最多不限
/*var reg4 = /^\d{6,}$/;
var str4 = "123454655555555555789";
alert( reg4.test(str4)  )
*/



//用户名最少6个字符，最多12个字符
/*
var reg5 = /^\w{6,12}$/;
var str5 = "123ab__44444a";
alert(  reg5.test(str5) );
*/


/*var reg6 = /^\d*$/;
//匹配数字，最少可以没有，最多不限制
var num6 = "";
alert(  reg6.test(num6) );*/


/*var reg7 = /^\d+$/;
//匹配数字，最少一次，最多不限制
var num7 = "1111111111111"；
alert(  reg7.test(num7) );*/



/*
var reg8 = /^\d?$/;
//匹配数字，最少0次，最多一次
var num8 = "11";
alert(  reg8.test(num8) );
*/

var reg1 = /com|cn/;
var str1 = "com";
alert(  reg1.test(str1) ); //com或cn都为true

/*
var reg1 = /[a-zA-Z]/;  // 匹配大写字母， 匹配小写字母
var str1 = "A";
alert( reg1.test(str1)  );

*/


/*var reg1 = /[A-Z]/i;  //   i===》不区分大小写
var str1 = "b";
alert( reg1.test(str1)  );*/



/*var reg1 = new RegExp("[A-Z]","i");
var str1 = "b";
alert( reg1.test(str1)  );*/




/*var reg1 = /a/g;
var str1 = "abc a a a";
var str = str1.replace(reg1,"#");
document.write(str);*/

/*
var reg1 = /baidu/g;
var str1 = "1.baidu\n2.baidu\n3.baidu";
var str = str1.replace(reg1,"#");
document.write(str);
*/


/*var reg1 = /^\d/gm;
var str1 = "1.baidu\n2.baidu\n3.baidu";
var str = str1.replace(reg1,"#");
document.write(str);*/

var reg2 = /[a-z]/igm;
var str2 = "a a a a A A";
var str = str2.replace(reg2,"#");
document.write(str);

/*var reg1 = /^(abc)$/;
var str1 = "abc";
alert( reg1.test(str1)  );*/



/*
var reg2 = /^ab{3}c{3}$/;  //C重复必须是3次
    var str2 = "abbbccc";
    alert(  reg2.test(str2)  );
*/



/*
var reg2 = /^(abc){3}$/;  //abc重复必须是3次
var str2 = "abcabcabc";
alert(  reg2.test(str2)  );
*/

/*var reg1 = /(a)/;
var str1 = "abc abc abc";
reg1.test(str1);
alert(  RegExp.$1  );//匹配到第一个分组内的内容*/



/*var reg2 = /(baidu) (taobao) (jd)/;
var str2 = "baidu taobao jd";
reg2.exec(str2);
//运行正则
alert(      RegExp.$3       );*/



var reg3 = /(taobao)/;
var str3 = "我是taobao";
var str = str3.replace(reg3,"<b style=‘color:red‘>$1</b>");
document.write(str);

/*
var reg1 = /a/g;
var str1 = "b a c a d";
var sh = str1.search(reg1);
document.write(sh);
*/


/*
var reg2 = /a/g;
var str2 = "ab ac ad";
//var arr = reg2.exec(str2);   //正则.exec这个方法==》不支持全局
//document.write(arr);

var arr = null;
while(arr=reg2.exec(str2)){

    document.write(arr);

}*/



/*
var reg3 = /a/g;
var str3 = "ab ac ad";
var arr = str3.match(reg3);
document.write(arr);
*/


var reg4 = /b/g;
var str4 = "ab bb cb";
var str = str4.replace(reg4,"*");
document.write(str);