当在 Javascript 中搜索 RegExp 模式来验证电子邮件地址时，我发现了 Facebook 使用的模式 here .
function is_email(a){return /^([\w!.%+\-])+@([\w\-])+(?:\.[\w\-]+)+$/.test(a);}
有人可以向我解释一下这种模式是如何工作的吗？据我所知，它正在三个位置寻找“单词字符”以及“@”字符。但一个好的解释会对我理解这一点有很大帮助。
最佳答案
有两个网站(据我所知)可以生成正则表达式模式的解释。
- regex101.com用文字解释该模式
- regexper.com以图形方式执行
这是我自己对该模式的解释:
^ # anchor the pattern to the beginning of the string; this ensures that
# there are no undesired characters before the email address, as regex
# matches might well be substrings otherwise
( # starts a group (which is unnecessary and incurs overhead)
[\w!.%+\-]
# matches a letter, digit, underscore or one of the explicitly mentioned
# characters (note that the backslash is used to escape the hyphen
# although that is not required if the hyphen is the last character)
)+ # end group; repeat one or more times
@ # match a literal @
( # starts another group (again unnecessary and incurs overhead)
[\w\-] # match a letter, digit, underscore or hyphen
)+ # end group; repeat one or more times
(?: # starts a non-capturing group (this one is necessary and, because
# capturing is suppressed, this one does not incur any overhead)
\. # match a literal period
[\w\-] # match a letter, digit, underscore or hyphen
+ # one or more of those
)+ # end group; repeat one or more times
$ # anchor the pattern to the end of the string; analogously to ^
所以，这将是一个稍微优化的版本:
/^[\w!.%+\-]+@[\w\-]+(?:\.[\w\-]+)+$/
关于javascript - Facebook 注册表单电子邮件验证模式，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/16318691/