Matching the regular expression of email address in php _ PHP Tutorial

Match the regular expression of the email address in php. A php regular expression matching mailbox address instance, mail address replace regular I commonly used regular expression matching: ^ [a-z] ([a-z0-9] * [-_]? [A-z0-9] +) * @ ([a-z0-9] * [-_]? [A-z0-9] +) + [\.] [a-z: an example of a regular expression matching the email address in php. replace the email address with the regular expression. my common regular expression is: /^ [a-z] ([a-z0-9] * [-_]? [A-z0-9] +) * @ ([a-z0-9] * [-_]? [A-z0-9] +) + [\.] [a-z] {2, 3} ([\.] [a-z] {2 })? $/I. For more information, see.

Php example

The following describes PHP as an example:

The code is as follows:
<? Php If (ereg ('/^ [a-z] ([a-z0-9] * [-_.]? [A-z0-9] +) * @ ([a-z0-9] * [-_]? [A-z0-9] +) + [.] [a-z] {2, 3} ([.] [a-z] {2 })? $/I; ", $ email )) { Echo "Your email address is correct !"; } Else { Echo "Please try again !"; } ?>

Note:
①/Content/I constitutes a case-insensitive regular expression; ^ match starts; $ match ends.

② [A-z] the e-mail prefix must start with an English letter

③ ([A-z0-9] * [-_]? [A-z0-9] +) * and _ a_2, aaa11, _ 1_a_2 match, and a1 _, aaff_33a _, a _ aa does not match, if it is a null character, but also match, * indicates 0 or more.

④ * Indicates 0 or multiple prefix characters.

⑤ [A-z0-9] * match 0 or more English letters or numbers; [-_]? Match 0 or 1 "-" because "-" cannot appear consecutively.

6 [a-z0-9] + match one or more English letters or numbers, because '-' cannot end

7 @ there must be @

Trim ([a-z0-9] * [-_]? [A-z0-9] +) + See above ([a-z0-9] * [-_]? [A-z0-9] +) * interpreted, but cannot be empty, + represents one or more.

Pipeline [.] treats special characters (.) as common characters. [a-z] {2, 3} matches two to three English letters, generally com or net.
Equals ([.] [a-z] {2 })? Match 0 or 1 [.] [a-z] {2} (for example. cn, etc.) I do not know whether the last part of .com.cn is generally two. if not, change {2} to {start word count, end word count}

Js example

The code is as follows:
Script Function Email (ee ){ Var emailreg = "^ \ w + @ \ w + \. \ w + (\. \ w +) * $ "; Var rege = new RegExp (emailreg, 'g '); Alert (rege. test (ee )); } Var ee1 = "12xwz @ 123e ^ rsrf6.csdfdfom. df "; Var ee2 = "12xwz@123ersrf6.csdfdfom.df "; Email (ee1 ); Email (ee2 ); Script

For better understanding of regular expressions, please learn the character string escape form
Here, you use a string to represent a regular expression, and the escape character must be represented by \. if you want to match, use \
^ \ W + @ \ w + \. \ w + (\. \ w +) * $
At the beginning, w word has one or more
@
Is a word
. There is one or more word
(\. \ W +) * No or more

Trim ([a-z0-9] * [-_]? [A-z0-9] +) * @ ([a-z0-9] * [-_]? [A-z0-9] +) + [\.] [a-z...