JScript Language Reference --------------------------------------------------------------------------------Regular Expression Syntax A regular expression is a pattern of text that consists of ordinary characters (for example, letters a through z) and special characters, known as metacharacters. The pattern describes one or more strings to match when searching a body of text. The regular expression serves as a template for matching a character pattern to the string being searched.Here are some examples of regular expression you might encounter:JScript VBScript Matches /^\[ \t]*$/ "^\[ \t]*$" Match a blank line. /\d{2}-\d{5}/ "\d{2}-\d{5}" Validate an ID number consisting of 2 digits, a hyphen, and another 5 digits. /<(.*)>.*<\/\1>/ "<(.*)>.*<\/\1>" Match an HTML tag. The following table contains the complete list of metacharacters and their behavior in the context of regular expressions:Character Description \ Marks the next character as either a special character, a literal, a backreference, or an octal escape. For example, 'n' matches the character "n". '\n' matches a newline character. The sequence '\\' matches "\" and "\(" matches "(". ^ Matches the position at the beginning of the input string. If the RegExp object's Multiline property is set, ^ also matches the position following '\n' or '\r'. $ Matches the position at the end of the input string. If the RegExp object's Multiline property is set, $ also matches the position preceding '\n' or '\r'. * Matches the preceding subexpression zero or more times. For example, zo* matches "z" and "zoo". * is equivalent to {0,}. + Matches the preceding subexpression one or more times. For example, 'zo+' matches "zo" and "zoo", but not "z". + is equivalent to {1,}. ? Matches the preceding subexpression zero or one time. For example, "do(es)?" matches the "do" in "do" or "does". ? is equivalent to {0,1} {n} n is a nonnegative integer. Matches exactly n times. For example, 'o{2}' does not match the 'o' in "Bob," but matches the two o's in "food". {n,} n is a nonnegative integer. Matches at least n times. For example, 'o{2,}' does not match the "o" in "Bob" and matches all the o's in "foooood". 'o{1,}' is equivalent to 'o+'. 'o{0,}' is equivalent to 'o*'.
意义：对于字符，通常表示按字面意义，指出接着的字符为特殊字符，不作解释。
例如：/b/匹配字符'b',通过在b 前面加一个反斜杠，也就是/b/，则该字符变成特殊字符，表示
匹配一个单词的分界线。
或者：
对于几个字符，通常说明是特殊的，指出紧接着的字符不是特殊的，而应该按字面解释。
例如：*是一个特殊字符，匹配任意个字符(包括0个字符)；例如：/a*/意味匹配0个或多个a。
为了匹配字面上的*，在a前面加一个反斜杠；例如：/a*/匹配'a*'。 字符^
意义：表示匹配的字符必须在最前边。
例如：/^A/不匹配"an A,"中的'A'，但匹配"An A."中最前面的'A'。 字符$
意义：与^类似，匹配最末的字符。
例如：/t$/不匹配"eater"中的't'，但匹配"eat"中的't'。 字符*
意义：匹配*前面的字符0次或n次。
例如:/bo*/匹配"A ghost booooed"中的'boooo'或"A bird warbled"中的'b'，但不匹配"A goat g
runted"中的任何字符。 字符+
意义：匹配+号前面的字符1次或n次。等价于{1,}。
例如：/a+/匹配"candy"中的'a'和"caaaaaaandy."中的所有'a'。 字符?
意义：匹配?前面的字符0次或1次。
例如：/e?le?/匹配"angel"中的'el'和"angle."中的'le'。 字符.
意义：(小数点)匹配除换行符外的所有单个的字符。
例如：/.n/匹配"nay, an apple is on the tree"中的'an'和'on'，但不匹配'nay'。
字符(x)
意义：匹配'x'并记录匹配的值。
例如：/(foo)/匹配和记录"foo bar."中的'foo'。匹配子串能被结果数组中的素[1], ..., [n] 返
回，或被RegExp对象的属性$1, ..., $9返回。 字符x|y
意义：匹配'x'或者'y'。
例如：/green|red/匹配"green apple"中的'green'和"red apple."中的'red'。 字符{n}
意义：这里的n是一个正整数。匹配前面的n个字符。
例如：/a{2}/不匹配"candy,"中的'a'，但匹配"caandy," 中的所有'a'和"caaandy."中前面的两个
'a'。 字符{n,}
意义：这里的n是一个正整数。匹配至少n个前面的字符。
例如：/a{2,}不匹配"candy"中的'a'，但匹配"caandy"中的所有'a'和"caaaaaaandy."中的所有'a' 字符{n,m}
意义：这里的n和m都是正整数。匹配至少n个最多m个前面的字符。
例如：/a{1,3}/不匹配"cndy"中的任何字符，但匹配 "candy,"中的'a'，"caandy," 中的前面两个
'a'和"caaaaaaandy"中前面的三个'a'，注意：即使"caaaaaaandy" 中有很多个'a'，但只匹配前面的三
个'a'即"aaa"。 字符[xyz]
意义：一字符列表，匹配列出中的任一字符。你可以通过连字符-指出一个字符范围。
例如：[abcd]跟[a-c]一样。它们匹配"brisket"中的'b'和"ache"中的'c'。 字符[^xyz]
意义：一字符补集，也就是说，它匹配除了列出的字符外的所有东西。 你可以使用连字符-指出一
字符范围。
例如：[^abc]和[^a-c]等价，它们最早匹配"brisket"中的'r'和"chop."中的'h'。 字符[b]
意义：匹配一个空格(不要与b混淆) 字符b
意义：匹配一个单词的分界线，比如一个空格(不要与[b]混淆)
例如：/bnw/匹配"noonday"中的'no'，/wyb/匹配"possibly yesterday."中的'ly'。 字符B
意义：匹配一个单词的非分界线
例如：/wBn/匹配"noonday"中的'on'，/yBw/匹配"possibly yesterday."中的'ye'。 字符cX
意义：这里的X是一个控制字符。匹配一个字符串的控制字符。
例如：/cM/匹配一个字符串中的control-M。 字符d
意义：匹配一个数字，等价于[0-9]。
例如：/d/或/[0-9]/匹配"B2 is the suite number."中的'2'。 字符D
意义：匹配任何的非数字，等价于[^0-9]。
例如：/D/或/[^0-9]/匹配"B2 is the suite number."中的'B'。 字符f
意义：匹配一个表单符 字符n
意义：匹配一个换行符 字符r
意义：匹配一个回车符 字符s
意义：匹配一个单个white空格符，包括空格，tab，form feed，换行符，等价于[ fnrtv]。
例如：/sw*/匹配"foo bar."中的' bar'。 字符S
意义：匹配除white空格符以外的一个单个的字符，等价于[^ fnrtv]。
例如：/S/w*匹配"foo bar."中的'foo'。 字符t
意义：匹配一个制表符 字符v
意义：匹配一个顶头制表符 字符w
意义：匹配所有的数字和字母以及下划线，等价于[A-Za-z0-9_]。
例如：/w/匹配"apple,"中的'a'，"$5.28,"中的'5'和"3D."中的'3'。 字符W
意义：匹配除数字、字母外及下划线外的其它字符，等价于[^A-Za-z0-9_]。
例如：/W/或者/[^$A-Za-z0-9_]/匹配"50%."中的'%'。 字符n
意义：这里的n是一个正整数。匹配一个正则表达式的最后一个子串的n的值(计数左圆括号)。 例如：/apple(,)sorange1/匹配"apple, orange, cherry, peach."中的'apple, orange'，下面
有一个更加完整的例子。
注意：如果左圆括号中的数字比n指定的数字还小，则n取下一行的八进制escape作为描述。 字符ooctal和xhex
意义：这里的ooctal是一个八进制的escape值，而xhex是一个十六进制的escape值，允许在一个正则表达式中嵌入ASCII码。
http://www.aspcool.com/lanmu/browse1.asp?ID=875&bbsuser=aspnet
A regular expression is a pattern of text that consists of ordinary characters (for example, letters a through z) and special characters, known as metacharacters. The pattern describes one or more strings to match when searching a body of text. The regular expression serves as a template for matching a character pattern to the string being searched.Here are some examples of regular expression you might encounter:JScript VBScript Matches
/^\[ \t]*$/ "^\[ \t]*$" Match a blank line.
/\d{2}-\d{5}/ "\d{2}-\d{5}" Validate an ID number consisting of 2 digits, a hyphen, and another 5 digits.
/<(.*)>.*<\/\1>/ "<(.*)>.*<\/\1>" Match an HTML tag.
The following table contains the complete list of metacharacters and their behavior in the context of regular expressions:Character Description
\ Marks the next character as either a special character, a literal, a backreference, or an octal escape. For example, 'n' matches the character "n". '\n' matches a newline character. The sequence '\\' matches "\" and "\(" matches "(".
^ Matches the position at the beginning of the input string. If the RegExp object's Multiline property is set, ^ also matches the position following '\n' or '\r'.
$ Matches the position at the end of the input string. If the RegExp object's Multiline property is set, $ also matches the position preceding '\n' or '\r'.
* Matches the preceding subexpression zero or more times. For example, zo* matches "z" and "zoo". * is equivalent to {0,}.
+ Matches the preceding subexpression one or more times. For example, 'zo+' matches "zo" and "zoo", but not "z". + is equivalent to {1,}.
? Matches the preceding subexpression zero or one time. For example, "do(es)?" matches the "do" in "do" or "does". ? is equivalent to {0,1}
{n} n is a nonnegative integer. Matches exactly n times. For example, 'o{2}' does not match the 'o' in "Bob," but matches the two o's in "food".
{n,} n is a nonnegative integer. Matches at least n times. For example, 'o{2,}' does not match the "o" in "Bob" and matches all the o's in "foooood". 'o{1,}' is equivalent to 'o+'. 'o{0,}' is equivalent to 'o*'.
? When this character immediately follows any of the other quantifiers (*, +, ?, {n}, {n,}, {n,m}), the matching pattern is non-greedy. A non-greedy pattern matches as little of the searched string as possible, whereas the default greedy pattern matches as much of the searched string as possible. For example, in the string "oooo", 'o+?' matches a single "o", while 'o+' matches all 'o's.
. Matches any single character except "\n". To match any character including the '\n', use a pattern such as '[.\n]'.
(pattern) Matches pattern and captures the match. The captured match can be retrieved from the resulting Matches collection, using the SubMatches collection in VBScript or the $0…$9 properties in JScript. To match parentheses characters ( ), use '\(' or '\)'.
(?:pattern) Matches pattern but does not capture the match, that is, it is a non-capturing match that is not stored for possible later use. This is useful for combining parts of a pattern with the "or" character (|). For example, 'industr(?:y|ies) is a more economical expression than 'industry|industries'.
(?=pattern) Positive lookahead matches the search string at any point where a string matching pattern begins. This is a non-capturing match, that is, the match is not captured for possible later use. For example 'Windows (?=95|98|NT|2000)' matches "Windows" in "Windows 2000" but not "Windows" in "Windows 3.1". Lookaheads do not consume characters, that is, after a match occurs, the search for the next match begins immediately following the last match, not after the characters that comprised the lookahead.
(?!pattern) Negative lookahead matches the search string at any point where a string not matching pattern begins. This is a non-capturing match, that is, the match is not captured for possible later use. For example 'Windows (?!95|98|NT|2000)' matches "Windows" in "Windows 3.1" but does not match "Windows" in "Windows 2000". Lookaheads do not consume characters, that is, after a match occurs, the search for the next match begins immediately following the last match, not after the characters that comprised the lookahead.
x|y Matches either x or y. For example, 'z|food' matches "z" or "food". '(z|f)ood' matches "zood" or "food".
[xyz] A character set. Matches any one of the enclosed characters. For example, '[abc]' matches the 'a' in "plain".
[^xyz] A negative character set. Matches any character not enclosed. For example, '[^abc]' matches the 'p' in "plain".
[a-z] A range of characters. Matches any character in the specified range. For example, '[a-z]' matches any lowercase alphabetic character in the range 'a' through 'z'.
[^a-z] A negative range characters. Matches any character not in the specified range. For example, '[^a-z]' matches any character not in the range 'a' through 'z'.
\b Matches a word boundary, that is, the position between a word and a space. For example, 'er\b' matches the 'er' in "never" but not the 'er' in "verb".
\B Matches a nonword boundary. 'er\B' matches the 'er' in "verb" but not the 'er' in "never".
\cx Matches the control character indicated by x. For example, \cM matches a Control-M or carriage return character. The value of x must be in the range of A-Z or a-z. If not, c is assumed to be a literal 'c' character.
\d Matches a digit character. Equivalent to [0-9].
\D Matches a nondigit character. Equivalent to [^0-9].
\f Matches a form-feed character. Equivalent to \x0c and \cL.
\n Matches a newline character. Equivalent to \x0a and \cJ.
\r Matches a carriage return character. Equivalent to \x0d and \cM.
\s Matches any whitespace character including space, tab, form-feed, etc. Equivalent to [ \f\n\r\t\v].
\S Matches any nonwhite space character. Equivalent to [^ \f\n\r\t\v].
\t Matches a tab character. Equivalent to \x09 and \cI.
\v Matches a vertical tab character. Equivalent to \x0b and \cK.
\w Matches any word character including underscore. Equivalent to '[A-Za-z0-9_]'.
\W Matches any nonword character. Equivalent to '[^A-Za-z0-9_]'.
\xn Matches n, where n is a hexadecimal escape value. Hexadecimal escape values must be exactly two digits long. For example, '\x41' matches "A". '\x041' is equivalent to '\x04' & "1". Allows ASCII codes to be used in regular expressions.
\num Matches num, where num is a positive integer. A reference back to captured matches. For example, '(.)\1' matches two consecutive identical characters.
\n Identifies either an octal escape value or a backreference. If \n is preceded by at least n captured subexpressions, n is a backreference. Otherwise, n is an octal escape value if n is an octal digit (0-7).
\nm Identifies either an octal escape value or a backreference. If \nm is preceded by at least nm captured subexpressions, nm is a backreference. If \nm is preceded by at least n captures, n is a backreference followed by literal m. If neither of the preceding conditions exist, \nm matches octal escape value nm when n and m are octal digits (0-7).
\nml Matches octal escape value nml when n is an octal digit (0-3) and m and l are octal digits (0-7).
\un Matches n, where n is a Unicode character expressed as four hexadecimal digits. For example, \u00A9 matches the copyright symbol (©). --------------------------------------------------------------------------------
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