请解释这个电子邮件验证正则表达式： [英] Please explain this e-mail validation regular expression:

问题描述

我有这个脚本使用正则表达式检查表单字段是否包含有效的电子邮件地址。请从声明解释我

I have this script uses regular expressions to check that a form field contains a valid email address.Please explain me from declare

var emailfilter=/^\w+[\+\.\w-]*@([\w-]+\.)*\w+[\w-]*\.([a-z]{2,4}|\d+)$/i;

谢谢

资料来源：

<script type="text/javascript">

/***********************************************
* Email Validation script- © Dynamic Drive (www.dynamicdrive.com)
* This notice must stay intact for legal use.
* Visit http://www.dynamicdrive.com/ for full source code
***********************************************/

var emailfilter=/^\w+[\+\.\w-]*@([\w-]+\.)*\w+[\w-]*\.([a-z]{2,4}|\d+)$/i

function checkmail(e){
var returnval=emailfilter.test(e.value)
if (returnval==false){
alert("Please enter a valid email address.")
e.select()
}
return returnval
}

</script>

<form>
<input name="myemail" type="text" style="width: 270px"> <input type="submit" onClick="return checkmail(this.form.myemail)" value="Submit" />

</form>

推荐答案

/ ^ \ w + [\ + \.\w - ] * @（[\w - ] + \。）* \w + [\w - ] * \（[AZ] {2,4}。| \ + +）$ / i

/ =开始表达

^ =匹配的字符串必须从这里开始，并且只能从这里开始

\ w =任何单词（字母，数字，下划线）

+ =匹配前面的表达式至少一次，无限次数

[] =匹配括号内的任何字符，但只匹配一个

\ + \。 =匹配文字 + 或。

\ w =另一个单词

- =匹配文字 -

* =匹配前一个表达式零或无限次


@ =匹配文字 @ 符号

（） =让一切都在里面将括号括起来（并制作它们） referencable）

[] =另一个字符集

\w - =匹配任何单词或文字 -

+ =另一个 1到无穷大量词

\。 =匹配另一个文字。

* =另一个 0到无穷大量词

\w + =至少匹配一个单词

[\w - ] * \。 =匹配一个单词或破折号至少零次，然后是文字。

（） =另一组

[az] {2,4} =匹配小写字母至少2次但不超过4次时代

| =或（与管道不匹配）

\d + =匹配至少1位数
$ =字符串的结尾

/ =结束表达式

i =测试 i nsensitive案例中的字符串方式

/ = Begin an expression
^ = The matched string must begin here, and only begin here
\w = any word (letters, digits, underscores)
+ = match previous expression at least once, unlimited number of times
[] = match any character inside the brackets, but only match one
\+\. = match a literal + or .
\w = another word
- = match a literal -
* = match the previous expression zero or infinite times
@ = match a literal @ symbol
() = make everything inside the parentheses a group (and make them referencable)
[] = another character set
\w- = match any word or a literal -
+ = another 1 to infinity quantifier
\. = match another literal .
* = another 0 to infinity quantifier
\w+ = match a word at least once
[\w-]*\. = match a word or a dash at least zero times, followed by a literal .
() = another group
[a-z]{2,4} = match lowercase letters at least 2 times but no more than 4 times
| = "or" (does not match pipe)
\d+ = match at least 1 digit
$ = the end of the string
/ = end an expression
i = test the string in a case i nsensitive manner

或者你不能ry 这个很棒的链接。你知道，无论如何。

Or you could try this awesome link. You know, whatever.

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