这个问题比一眼看起来更难回答。

世界各地有大量的人正在寻找“统治他们所有”,但事实是,有大量的电子邮件提供商。

为什么? 根据 RFC: https://en.wikipedia.org/wiki/Email_address#RFC_specification。

The local-part of the email address may use any of these ASCII characters:

- uppercase and lowercase Latin letters A to Z and a to z;
- digits 0 to 9;
- special characters !#$%&'*+-/=?^_`{|}~;
- dot ., provided that it is not the first or last character unless quoted, and provided also that it does not appear consecutively unless quoted (e.g. John..Doe@example.com is not allowed but "John..Doe"@example.com is allowed);[6]
Note that some mail servers wildcard local parts, typically the characters following a plus and less often the characters following a minus, so fred+bah@domain and fred+foo@domain might end up in the same inbox as fred+@domain or even as fred@domain. This can be useful for tagging emails for sorting, see below, and for spam control. Braces { and } are also used in that fashion, although less often.
- space and "(),:;<>@[\] characters are allowed with restrictions (they are only allowed inside a quoted string, as described in the paragraph below, and in addition, a backslash or double-quote must be preceded by a backslash);
- comments are allowed with parentheses at either end of the local-part; e.g. john.smith(comment)@example.com and (comment)john.smith@example.com are both equivalent to john.smith@example.com.

A__z/J0hn.sm{it!}h_comment@example.com.co

如果你尝试这个地址我赌它将失败在所有的或大部分的regex发布在整个网络上. 但记住这个地址遵循RFC规则,所以它是公平有效的。

想象一下我的失望,因为我无法在任何地方注册与这些 regex 检查!!!

如何处理,是的?

"very.(),:;<>[]\".VERY.\"very@\\ \"very\".unusual"@strange.example.com

在这样做时,一个好做法是“重新输入您的电子邮件”输入,以避免用户输入错误,如果这对您来说不够,请添加一个提前提交的模型窗口,标题为“这是您的当前电子邮件吗?”然后用户输入的电子邮件在一个H2标签中,您知道,清楚地显示他们输入的电子邮件,然后一个“是的,提交”按钮。

有一件事你必须明白,第二件事你决定使用一个常规的表达式来验证电子邮件:这可能不是一个好主意,一旦你达成协议,有很多实施,可以让你在那里半路,这篇文章会把它们合成好。

简而言之,但是,唯一的方式是绝对的,肯定的是,用户输入的是实际上一个电子邮件是实际上发送一个电子邮件,看看发生了什么。

JavaScript 可以匹配一个常规表达式:

emailAddress.match( / some_regex /);

下面是RFC22电子邮件的常规表达式:

^((?>[a-zA-Z\d!#$%&'*+\-/=?^_`{|}~]+\x20*|"((?=[\x01-\x7f])[^"\\]|\\[\x01-\x7f])*
"\x20*)*(?<angle><))?((?!\.)(?>\.?[a-zA-Z\d!#$%&'*+\-/=?^_`{|}~]+)+|"((?=[\x01-\x
7f])[^"\\]|\\[\x01-\x7f])*")@(((?!-)[a-zA-Z\d\-]+(?<!-)\.)+[a-zA-Z]{2,}|\[(((?(?<
!\[)\.)(25[0-5]|2[0-4]\d|[01]?\d?\d)){4}|[a-zA-Z\d\-]*[a-zA-Z\d]:((?=[\x01-\x7f])
[^\\\[\]]|\\[\x01-\x7f])+)\])(?(angle)>)$

所有电子邮件地址都包含一个“at”(即 @)符号。

email.includes('@')

或者,如果您需要支持 IE/older 浏览器:

email.indexOf('@') > 0

即使你能完全确定一个电子邮件是否是RFC合成有效,这不会告诉你它是否属于提供它的人。

要做到这一点,请发送验证消息。

最好的一个 :D(RFC友好和没有错误“太复杂”) :

function    isMail(mail)
{
    pattuser = /^([A-Z0-9_%+\-!#$&'*\/=?^`{|}~]+\.?)*[A-Z0-9_%+\-!#$&'*\/=?^`{|}~]+$/i;
    pattdomain = /^([A-Z0-9-]+\.?)*[A-Z0-9-]+(\.[A-Z]{2,9})+$/i;

    tab = mail.split("@");
    if (tab.length != 2)
        return false;
    return (pattuser.test(tab[0]) && pattdomain.test(tab[1]));
}

在您的验证函数中使用此代码:

var emailID = document.forms["formName"]["form element id"].value;
atpos = emailID.indexOf("@");
dotpos = emailID.lastIndexOf(".");
if (atpos < 1 || ( dotpos - atpos < 2 ))
{
    alert("Please enter correct email ID")
    return false;
}

您可以使用 jQuery. 内部规则定义:

eMailId: {
    required: true,
    email: true
}