JS Regular expression notation

Basic knowledge of a JavaScript regular expression

1 JavaScript regular object creation and usage

Declaring a JavaScript regular expression

var recat = new RegExp ("cat");
You can also
var recat =/cat/; Perl Style (recommended)

2 Learn the most common test exec match search replace split 6 methods

1) test checks whether the specified string exists

var data = "123123";
var recat =/123/gi;
Alert (recat.test (data)); True

Check if the character exists G continue down I case-insensitive

2) Exec return query value

var data = "123123,213,12312,312,3,cat,cat,dsfsdfs,";
var recat =/cat/i;
Alert (recat.exec (data)); Cat

3) match gets query array

var data = "123123,213,12312,312,3,cat,cat,dsfsdfs,";
var recat =/cat/gi;
var arrmactches = Data.match (recat)

for (Var i=0;i < arrmactches.length; i++)
{
Alert (Arrmactches[i]); Cat Cat
}

4) search returns location similar to IndexOf

var data = "123123,213,12312,312,3,cat,cat,dsfsdfs,";
var recat =/cat/gi;
Alert (Data.search (Recat)); 23


5) Replace replacement character with regular substitution

var data = "123123,213,12312,312,3,cat,cat,dsfsdfs,";
var recat =/cat/gi;
Alert (Data.replace (Recat, "libinqq"));

6) split using regular split array

var data = "123123,213,12312,312,3,cat,cat,dsfsdfs,";
var recat =/\,/;
var arrdata = Data.split (recat);

for (var i = 0; i < arrdata.length; i++)
{
Alert (Arrdata[i]);
}

3 Learning the Simple class negative class scope class combination class

Simple class
var data = "1LIBINQQ,2LIBINQQ,3LIBINQQ,4LIBINQQ";
var recat =/[123]libinqq/gi;
var arrdata = Data.match (recat);

for (var i = 0; i < arrdata.length; i++)
{
Alert (Arrdata[i]); 1LIBINQQ 2LIBINQQ 3LIBINQQ
}

Negative to Class
var data = "ALIBINQQ,1LIBINQQ,2LIBINQQ,3LIBINQQ,4LIBINQQ"; \u0062cf
var recat =/[^a123]libinqq/gi;
var arrdata = Data.match (recat);

for (var i = 0; i < arrdata.length; i++)
{
Alert (Arrdata[i]); 4libinqq
}

Scope class
var data = "Libinqq1,libinqq2,libinqq3,libinqq4,libinqq5"; \u0062cf
var recat =/libinqq[2-3]/gi;
var arrdata = Data.match (recat);

for (var i = 0; i < arrdata.length; i++)
{
Alert (Arrdata[i]); LIBINQQ2 libinqq3
}

Combination Class
var data = "a,b,c,w,1,2,3,5"; \u0062cf
var recat =/[a-q1-4\n]/gi;
var arrdata = Data.match (recat);

for (var i = 0; i < arrdata.length; i++)
{
Alert (Arrdata[i]); A b C 1 2 3
}

JS Regular expression notation