What does the regular expression /ig mean in javascript

In JavaScript regular expressions, "/ig" means "perform global matching and ignore case" and is a modifier, where the modifier "i" is used to indicate that execution is case-insensitive. Match, the modifier "g" is used to indicate that a global match is performed.

The operating environment of this tutorial: Windows 10 system, JavaScript version 1.8.5, Dell G3 computer.

What does the regular expression /ig mean in javascript

The difference and meaning of /i,/g,/ig,/gi,/m in regular expressions

/i (ignore case)
/g (Full-text search for all matching characters)
/m (Multi-line search)
/gi (Full-text search, ignore case)
/ig( Search in full text, ignore case)

Modifier

Modifier	Description
i	Perform case-insensitive matching.
g	Perform global matching (find all matches instead of stopping after the first match is found).
m	Perform multi-line matching.

Square brackets

Square brackets are used to find characters within a range:

Expression	Description
[abc]	Finds any characters between square brackets.
[^abc]	Find any characters not between square brackets.
[0-9]	Find any number from 0 to 9.
[a-z]	Find any character from lowercase a to lowercase z.
[A-Z]	Find any character from uppercase A to uppercase Z.
[A-z]	Find any character from uppercase A to lowercase z.
[adgk]	Find any character within the given set.
[^adgk]	Find any character outside the given set.
(red|blue|green)	Find any specified option.

Metacharacters

Metacharacters are characters with special meanings:

Metacharacter	Description
.	Finds a single character, except newlines and line terminators.
w	Find word characters.
W	Find non-word characters.
d	Find numbers.
D	Find non-numeric characters.
s	Find whitespace characters.
S	Find non-whitespace characters.
b	Find matches at the beginning or end of a word.
B	Find matches that are not at the beginning or end of a word.
	Find NUL characters.
n	Find newlines.
f	Find the form feed character.
#r	Find the carriage return character.
t	Find the tab character.
v	Find the vertical tab character.
xxx	Find the character specified by the octal number xxx.
xdd	Find the character specified by the hexadecimal number dd.
uxxxx	Find the Unicode character specified in the hexadecimal number xxxx.

Quantifier

Quantifier	Description
n	Matches any string containing at least one n.
n*	Matches any string containing zero or more n.
n?	Matches any string containing zero or one n.
n{X}	Matches a string containing X sequences of n.
n{X,Y}	Matches a string containing a sequence of X or Y n.
n{X,}	Matches a string containing a sequence of at least X n.
n$	Matches any string ending in n.
^n	Matches any string starting with n.
?=n	Matches any string immediately followed by the specified string n.
?!n	Matches any string that is not immediately followed by the specified string n.

RegExp Object Properties

FF: Firefox, IE: Internet Explorer

Properties	Description	FF	IE
global	#RegExp Whether the object has flag g.	1	4
ignoreCase	RegExp Whether the object has flag i.	1	4
lastIndex	An integer indicating the character position to start the next match.	1	4
multiline	RegExp Whether the object has flag m.	1	4
source	The source text of the regular expression.	1	4

Метод объекта RegExp

FF: Firefox, IE: Internet Explorer

Метод	Описание	FF	IE
compile	Компилируйте регулярное выражение.	1	4
exec	Получает значение, указанное в строке. Возвращает найденное значение и определяет его положение.	1	4
test	Получает значение, указанное в строке. Возвращает истину или ложь.	1	4

Методы объектов String, поддерживающих регулярные выражения

FF: Firefox, IE: Интернет Explorer

Метод	#Описание	FF	IE
# search	Получает значения, соответствующие регулярному выражению.	1	4
match	Найдите совпадение для одного или нескольких регулярных выражений.	1	4
replace	Замените подстроку, соответствующую регулярному выражению.	1	4
split	Разделение строки в массив строк.

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