1. Regular-expression literal characters Character MatchesAlphanumeric character Itself \ 0 The NUL character (\ u0000) \ t Tab (\ u0009) \ n Newline (\ u000A) \ v Vertical tab (\ u000B) \ f Form feed (\ u000C) \ r Carriage return (\ u000D) \ xnn The Latin character specified by the hexadecimal number nn; for example, \ x0A is the same as \ n \ uxxxx The Unicode character specified by the hexadecimal number xxxx; for example, \ u0009 is the same as \ t \ cX The control character ^ X; for example, \ cJ is equivalent to the newline character \ n
2. Regular expression character classes Character Matches
[...] Any one character between the brackets. [^...] any one character not between the brackets .. any character t newline or another Unicode line terminator. \ w Any ASCII word character. equivalent to [a-zA-Z0-9 _]. \ W Any character that is not an ASCII word character. equivalent to [^ a-zA-Z0-9 _]. \ s Any Unicode whitespace character. \ S Any character that is not Unicode whitespace. note that \ w and \ S are not the same thing. \ d Any ASCII digit. equivalent to [0-9]. \ D Any character other than an ASCII digit. equivalent to [^ 0-9]. [\ B] A literal backspace (special case ).
3. Regular expression repetition characters Character Meaning{N, m} Match the previous item at least n times but no more than m times. {n,} Match the previous item n or more times. {n} Match exactly n occurrences of the previous item .? Match zero or one occurrences of the previous item. that is, the previous item is optional. equivalent to {0, 1 }. + Match one or more occurrences of the previous item. equivalent to {1 ,}. * Match zero or more occurrences of the previous item. equivalent to {0 ,}.
4. Regular expression alternation, grouping, and reference characters Character Meaning| Alternation. match either the subexpression to the left or the subexpression to the right. (...) grouping. group items into a single unit that can be used with *, + ,?, |, And so on. Also remember the characters that match this group for use with later references .(? :...) Grouping only. group items into a single unit, but do not remember the characters that match this group. \ n Match the same characters that were matched when group number n was first matched. groups are subexpressions within (possibly nested) parentheses. group numbers are assigned by counting left parentheses from left to right. groups formed (? : Are not numbered.
5. Regular-expression anchor characters Character Meaning^ Match the beginning of the string and, in multiline searches, the beginning of a line. $ Match the end of the string and, in multiline searches, the end of a line. \ B Match a word boundary. that is, match the position between a \ w character and a \ W character or between a \ w character and the beginning or end of a string. (Note, however, that [\ B] matches backspace .) \ B Match a position that is not A word boundary .(? = P) A positive lookahead assertion. Require that the following characters match the pattern p, but do not include those characters in the match .(?! P) A negative lookahead assertion. Require that the following characters do not match the pattern p.
6. Regular-expression flags Character MeaningI Perform case-insensitive matching. g Perform a global matchthat is, find all matches rather than stopping after the first match. m Multiline mode. ^ matches beginning of line or beginning of string, and $ matches end of line or end of string.
String. replace (regexp, replacement)
Characters Replacement $1, $2,..., $99 The text that matched the 1st through 99th parenthesized subexpression within regexp $ & The substring that matched regexp $' The text to the left of the matched substring $' The text to the right of the matched substring $ A literal dollar sign name. replace (/(\ w +) \ s *, \ s * (\ w +)/, "$2 $1"); text. replace (/"([^"] *) "/g," ''$1'' "); text. replace (/\ B \ w + \ B/g, function (word) {return word. substring (0, 1 ). toUpperCase () + word. substring (1 );});