Only numbers can be entered: "^[0-9]*$".
Only n digits can be entered: "^\d{n}$".
You can enter at least n digits: "^\d{n,}$".
You can enter only the number of m~n digits:. "^\d{m,n}$"
Only numbers beginning with 0 and not 0 can be entered: ^ (0|[ 1-9][0-9]*) $ ".
You can only enter positive real numbers with two decimal digits: ^[0-9]+ (. [ 0-9]{2})? $ ".
You can only enter positive real numbers with 1~3 decimal places: ^[0-9]+ (. [ 0-9]{1,3})? $ ".
You can only enter a Non-zero positive integer: "^\+?" [1-9] [0-9]*$].
You can only enter a Non-zero negative integer: "^\-[1-9][]0-9" *$.
You can only enter characters with a length of 3: "^. {3}$ ".
You can only enter a string of 26 English letters: "^[a-za-z]+$".
You can only enter a string consisting of 26 uppercase letters: "^[a-z]+$".
You can only enter a string consisting of 26 lowercase English letters: "^[a-z]+$".
You can only enter a string consisting of numbers and 26 English letters: "^[a-za-z0-9]+$".
You can only enter a string of numbers, 26 English letters, or underscores: "^\w+$".
Verify user password: "^[a-za-z]\w{5,17}$" is the correct format: start with a letter, length between 6~18, can only contain characters, numbers, and underscores.
Verify that there are ^%& ',; =?$\ ' and other characters: "[^%& ',; =?$\x22]+".
Only Chinese characters can be entered: "^[\u4e00-\u9fa5]{0,}$"
Verify email Address: "^\w+ ([-+.] \w+) *@\w+ ([-.] \w+) *\.\w+ ([-.] \w+) *$ ".
Verify InternetURL: "^http://%28[/\w-]+\." +[\w-]+ (/[\w-./?%&=]*)? $ ".
Verify phone Number: "^ (\ (\d{3,4}-) |\d{3.4}-)? \d{7,8}$" The correct format is: "Xxx-xxxxxxx", "xxxx-xxxxxxxx", "xxx-xxxxxxx", "xxx-xxxxxxxx", " XXXXXXX "and" XXXXXXXX ".
Verify ID Number (15-bit or 18-digit): "^\d{15}|\d{18}$".
Verify 12 months of the year: "^" (0?[ 1-9]|1[0-2]) $ "The correct format is:" 01 "~" 09 "and" 1 "~" 12 ".
Verify one months of 31 days: "^ (0?[ 1-9]) | ((1|2) [0-9]) |30|31) $ "the correct format is;" 01 "~" 09 "and" 1 "~" 31 ".
Use regular expressions to restrict the entry of text boxes in a Web page's form:
The regular expression limit can only be entered in Chinese: onkeyup= "value=value.replace (/[^\u4e00-\u9fa5]/g,") "Onbeforepaste=" Clipboarddata.setdata (' Text ', Clipboarddata.getdata (' text '). Replace (/[^\u4e00-\u9fa5]/g, ') "
Only full-width characters can be entered with regular expression restrictions: onkeyup= "Value=value.replace (/[^\uff00-\uffff]/g,") "Onbeforepaste=" Clipboarddata.setdata (' Text ', Clipboarddata.getdata (' text '). Replace (/[^\uff00-\uffff]/g, ') "
Only numbers can be entered with regular expression restrictions: onkeyup= "Value=value.replace (/[^\d]/g,") "Onbeforepaste=" Clipboarddata.setdata (' text ', Clipboarddata.getdata (' text '). Replace (/[^\d]/g, ') "
Only numbers and English can be entered with regular expression restrictions: onkeyup= "Value=value.replace (/[\w]/g,") "Onbeforepaste=" Clipboarddata.setdata (' text ', Clipboarddata.getdata (' text '). Replace (/[^\d]/g, ') "
You have to use regular expressions to extract the filename from the URL address of the JavaScript program, the following result is Page1
S= "Http://www.jb51.net/about.htm"
S=s.replace (/(. *\/) {0,} ([^\.] +). */ig, "$"
Alert (s)
Match Double-byte characters (including Chinese characters): [^\x00-\xff]
Application: Computes the length of the string (a double-byte character length meter 2,ascii character 1)
String.prototype.len=function () {return This.replace ([^\x00-\xff]/g, "AA"). Length;}
A regular expression that matches a blank row: \n[\s|] *\r
Regular expression matching HTML tags:/< (. *) >.*<\/\1>|< (. *) \/>/
Matching a regular expression with a trailing space: (^\s*) | (\s*$)
String.prototype.trim = function ()
{
Return This.replace (/(^\s*) | ( \s*$)/g, "");
}
To decompose and transform an IP address using a regular expression:
The following is a JavaScript program that uses a regular expression to match an IP address and converts an IP address to a corresponding numeric value:
function IP2V (IP)
{
re=/(\d+) \. (\d+) \. (\d+) \. (\d+)/g//matching the regular expression of the IP address
if (Re.test (IP))
{
Return Regexp.$1*math.pow (255,3)) +regexp.$2*math.pow (255,2)) +regexp.$3*255+regexp.$4*1
}
Else
{
throw new Error ("not a valid IP address!")
}
}
However, if the above program does not use a regular expression, and the split function directly to decompose may be simpler, the program is as follows:
var ip= "10.100.20.168"
Ip=ip.split (".")
Alert ("IP value is:" + (IP[0]*255*255*255+IP[1]*255*255+IP[2]*255+IP[3]*1))
Symbolic Explanation:
Character
Describe
\
Marks the next character as a special character, or a literal character, or a backward reference, or a octal escape character. For example, ' n ' matches the character ' n '. ' \ n ' matches a newline character. Sequence ' \ ' matches ' \ ' and ' \ (' Matches ' (".
^
Matches the start position of the input string. If the Multiline property of the RegExp object is set, ^ also matches the position after ' \ n ' or ' \ R '.
$
Matches the end position of the input string. If the Multiline property of the RegExp object is set, the $ also matches the position before ' \ n ' or ' \ R '.
*
Matches the preceding subexpression 0 or more times. For example, zo* can match "z" and "Zoo". * is equivalent to {0,}.
+
Matches the preceding subexpression one or more times. For example, ' zo+ ' can match "Zo" and "Zoo", but cannot match "Z". + is equivalent to {1,}.
?
Match the preceding subexpression 0 times or once. For example, "Do (es)" can match "do" in "do" or "does". is equivalent to {0,1}.
N
n is a non-negative integer. Matches the determined n times. For example, ' o{2} ' cannot match ' o ' in ' Bob ', but can match two o in ' food '.
{N,}
n is a non-negative integer. Match at least n times. For example, ' o{2,} ' cannot match ' o ' in ' Bob ' but can match all o in ' Foooood '. ' O{1,} ' is equivalent to ' o+ '. ' O{0,} ' is equivalent to ' o* '.
{N,m}
M and n are nonnegative integers, of which n <= M. Matches n times at least and matches up to M times. For example, "o{1,3}" will match the first three o in "Fooooood". ' o{0,1} ' is equivalent to ' o '. Notice that there is no space between the comma and the two number.
?
When the character is immediately following any of the other qualifiers (*, +,?, {n}, {n,}, {n,m}), the matching pattern is not greedy. Non-greedy patterns match as few strings as possible, while the default greedy pattern matches as many of the searched strings as possible. For example, for the string "oooo", ' o+? ' will match a single "O", and ' o+ ' will match all ' o '.
.
Matches any single character except "\ n". To match any character including ' \ n ', use a pattern like ' [. \ n] '.
(pattern)
Match pattern and get this match. The obtained matches can be obtained from the resulting matches collection, use the Submatches collection in VBScript, and use the $0...$9 property in JScript. To match the parentheses character, use ' \ (' or ' \ ').
(?:p Attern)
Matches pattern but does not get a matching result, which means it is a non fetch match and is not stored for later use. This is useful for combining parts of a pattern with the "or" character (|). For example, ' Industr (?: y|ies) is a more abbreviated expression than ' industry|industries '.
(? =pattern)
Forward lookup, matching the find string at the beginning of any string matching pattern. This is a non-fetch match, that is, the match does not need to be acquired for later use. For example, ' Windows (? =95|98| nt|2000) ' Can match windows in Windows 2000, but cannot match windows in Windows 3.1. It does not consume characters, that is, after a match occurs, the next matching search begins immediately after the last match, instead of starting after the character that contains the pre-check.
(?! Pattern
Negative pre-check, matches the lookup string at the beginning of any mismatched pattern string. This is a non-fetch match, that is, the match does not need to be acquired for later use. For example, ' Windows (?! 95|98| nt|2000) ' Can match windows in Windows 3.1, but cannot match windows in Windows 2000. It does not consume characters, that is, after a match occurs, the next matching search begins immediately after the last match, instead of starting after the character that contains the pre-check.
X|y
Match x or Y. For example, ' Z|food ' can match "z" or "food". ' (z|f) Ood ' matches ' zood ' or ' food '.
[XYZ]
Character set combination. Matches any one of the characters contained. For example, ' [ABC] ' can match ' a ' in ' plain '.
[^XYZ]
Negative character set combination. Matches any characters that are not included. For example, ' [^ABC] ' can match ' P ' in ' plain '.
[A-z]
The range of characters. Matches any character within the specified range. For example, ' [A-z] ' can match any lowercase alphabetic character in the range ' a ' to ' Z '.
[^a-z]
Negative character range. Matches any character that is not in the specified range. For example, ' [^a-z] ' can match any character that is not in the range of ' a ' to ' Z '.
\b
Matches a word boundary, which is the position between the word and the space. For example, ' er\b ' can match ' er ' in ' never ', but cannot match ' er ' in ' verb '.
\b
Matches a non-word boundary. ' er\b ' can match ' er ' in ' verb ', but cannot match ' 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 one-a-Z or a-Z. Otherwise, c is treated as a literal ' C ' character.
\d
Matches a numeric character. equivalent to [0-9].
\d
Matches a non-numeric character. equivalent to [^0-9].
\f
Matches a page feed character. Equivalent to \x0c and \CL.
\ n
Matches a line feed character. Equivalent to \x0a and \CJ.
\ r
Matches a carriage return character. Equivalent to \x0d and \cm.
\s
Matches any white space character, including spaces, tabs, page breaks, and so on. equivalent to [\f\n\r\t\v].
\s
Matches any non-white-space character. equivalent to [^ \f\n\r\t\v].
\ t
Matches a tab character. Equivalent to \x09 and \ci.
\v
Matches a vertical tab. Equivalent to \x0b and \ck.
\w
Matches any word character that includes an underscore. Equivalent to ' [a-za-z0-9_] '.
\w
Matches any non word character. Equivalent to ' [^a-za-z0-9_] '.
\xn
Matches n, where n is the hexadecimal escape value. The hexadecimal escape value must be a determined two digits long. For example, ' \x41 ' matches ' A '. ' \x041 ' is equivalent to ' \x04 ' & ' 1 '. You can use ASCII encoding in regular expressions ...
\num
Matches num, where num is a positive integer. A reference to the match that was obtained. For example, ' (.) \1 ' matches two consecutive identical characters.
\ n
Identifies a octal escape value or a backward reference. n is a backward reference if you have at least n obtained subexpression before \ nthe. Otherwise, if n is an octal number (0-7), then N is an octal escape value.
\nm
Identifies a octal escape value or a backward reference. NM is a backward reference if at least NM has obtained the subexpression before \nm. If there are at least N fetches before \nm, then n is a backward reference followed by a literal m. If all the preceding conditions are not satisfied, if both N and M are octal digits (0-7), then \nm will match octal escape value nm.
\nml
If n is an octal number (0-3) and both M and L are octal digits (0-7), the octal escape value NML is matched.
\un
Matches n, where N is a Unicode character represented in four hexadecimal digits. For example, \u00a9 matches the copyright symbol (?).