Dynamic Web pages make PHP regular expressions commonly used

Matching regular expressions for Chinese characters: [U4E00-U9FA5]

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:/< (. *) >.*</>|< (. *)/>/

Matching a regular expression with a trailing space: (^s*) | (s*$)

Application: JavaScript does not have a trim function like VBScript, we can use this expression to implement, as follows:

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 regular expressions for IP addresses
if (Re.test (IP)) {
Return Regexp.*math.pow (255,3)) Regexp.*math.pow (255,2)) regexp.*255 regexp.*1
}
else {
throw new Error ("not a valid IP address!")
}
}

However, if the above program does not use regular expressions, 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))

Regular expression matching an email address: w ([-.] W) *@w ([-.] W) *.W ([-.] W) *

A regular expression that matches the URL of the URL: http://([w].) [W] (/[w-./?%&=]*)?

An algorithmic program that uses regular expressions to remove repetitive characters from a string:

var s= "Abacabefgeeii"
var s1=s.replace (/(.). */g, "")
var re=new RegExp ("[" S1 "]", "G")
var s2=s.replace (Re, "")
Alert (S1 s2)//Result: ABCEFGI

JavaScript program that extracts the filename from the URL address using a regular expression, the following result is Page1

S= "Http://www.etoow.com/page1.htm"
S=s.replace (/(. */) ([^.]). */ig, "")
Alert (s)

Use regular expressions to restrict the entry of text boxes in a Web page's form:

Only Chinese can be entered with regular expression restrictions:

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, ') "

You can only enter numbers and English with regular expression restrictions:

Onkeyup= "Value=value.replace (/[w]/g,") "Onbeforepaste=" Clipboarddata.setdata (' text ', Clipboarddata.getdata (' Text '). Replace (/[^d]/g, "")