Pattern Matching with Regular Expressions

In JavaScript, regular expressions are accomplished by using RegExp objects. You can either define a regular expression with the RegExp() constructor, or by using the more common syntax: <code> var pattern = /s$/; var pattern = new RegExp(“s$”); </code> ===== Literal Characters ===== ^Character ^Matches ^ |Alphanumeric 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 hexidecimal number nn; for example, \x0A is the same as \n | |\uxxxx |The Unicode character specified by the hexidecimal 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 | ===== Punctuation characters with special meaning ===== <code> ^ $ . * + ? = ! : | \ / ( ) [ ] { } </code> ===== Character Classes ===== ^Character ^Matches ^ |[…] |Any one character between the brackets | |[^…] |Any one character not between the brackets | |. |Any character except 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) | ===== Repetition ===== ^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 occurences of the previous item | |? |Match zero or one ocurrences 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,} | - enter more table references