Commonly used regular expressions

xiaoxiao2021-03-06  110

Can't enter the regular expression of illegal characters

^ (?: [/ u4e00- / u9fa5] * / w * / s *) $

Other common regular expressions

Regular expressions matching Chinese characters: [/ u4e00- / u9fa5]

Match double-byte characters (including Chinese characters): [^ / X00- / XFF]

Application: Calculate the length of the string (a double-byte character length 2, ASCII characters 1)

String.prototype.len = function () {return this.Replace ([^ / X00- / XFF] / g, "aa"). Length;}

Regular expression of matching blank line: / n [/ s |] * / r

Matching the regular expression of HTML tag: / <(. *)>. * | <(. *) //> /

Regular expressions matching the first tail space: (^ / s *) | (/ s * $)

Application: There is no TRIM function like VBScript in JavaScript, we can use this expression to be implemented, as follows:

String.prototype.trim = function ()

{

Return this.Replace (/ (^ / s *) | (/ s * $) / g, "");

}

Using regular expressions to decompose and convert IP addresses:

Below is the JavaScript program that uses the regular expression to match the IP address and convert the IP address into the corresponding value:

Function IP2V (IP)

{

RE = / (/ d ) /. (/ d ) /. (/ d ) /. (/ d ) / g // Match 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, the above program does not use a regular expression, and directly use the SPLIT function 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))

Match the regular expression of the email address: / w ([- .] / W ) * @ / w ([-.] / W ) * /. / W ([-.] / W ) *

Matching URL URL regular expressions: http: // ([/ w-] /.) [/ W-] (/ [/ w- ./?%&=]*)?

Using the regular expression to remove the algorithm program of repeated characters in the strings: [Note: This program is incorrect, the reason is seen in this post Reply]

Var s = "abacabefgeeii"

Var S1 = S.Replace (/( (.).*/ 1 / g, "$ 1")

VAR RE = New Regexp ("[" S1 "]", "G")

Var s2 = s.replace (re, "")

Alert (S1 S2) / / The result is: Abcefgi

I originally posted a way to find an expression on 9CBS to implement the method of removing the repeating character, and I finally didn't find it, this is the simplest implementation method I can think of. The idea is to use the retrieval to remove the repeated characters, and then establish a second expression with a duplicate character, take the non-repetitive character, and the two are connected. This method may not apply for a string that requires the character sequence. You have to extract the JavaScript program of the file name from the URL address using a regular expression. The following results are page1

s = "http://www.9499.net/page1.htm"

s = s.Replace {0,} ([^ /.] ). * / ig, "$ 2")

Alert (s)

Use the regular expression to limit the text box in the text box in the web form:

Use the regular expression restrictions can only be entered in Chinese: οNKEYUP = "value = value.replace (/ [^ / U4E00- / U9FA5] / g, '')" onbeforepaste = "ClipboardData.SetData ('Text', ClipboardData.Getdata) 'Text'). Replace (/ [^ / U4E00- / U9FA5] / g, '')) "

Use the regular expression to limit only full-width characters: οnkeyup = "value = value.replace (/ [^ / uff00- / uffff) / g, ')" onbeforepaste = "clipboardData.setdata (' Text ', ClipboardData.Getdata) ('text'). Replace (/ [^ / UFF00- / UFFFFF] / g, '')) "

Use regular expressions to limit only numbers: οnkeyup = "value = value.replace (/ [^ / d] / g, '')" onbeforepaste = "ClipboardData.SetData ('Text', ClipboardData.Getdata ('Text' ) .Replace (/ [^ / d] / g, ')) ")

Use regular expressions to limit only numbers and English: οNKEYUP = "value = value.replace (/ [/ w] / g, '')" onbeforepaste = "ClipboardData.SetData ('Text', ClipboardData.Getdata ('Text ') .Replace (/ [^ / d] / g,'))

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