Have you looked at PHP’s filter_ functions? They’re not perfect, but they do a fairly decent job in my experience. Example usage (returns boolean): filter_var($someEmail, FILTER_VALIDATE_EMAIL);
Using regular expressions is probably the best way. You can see a bunch of tests here (taken from chromium) const validateEmail = (email) => { return String(email) .toLowerCase() .match( /^(([^<>()[\]\\.,;:\s@”]+(\.[^<>()[\]\\.,;:\s@”]+)*)|(“.+”))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/ ); }; Here’s the example of a regular expression that accepts unicode: const re = /^(([^<>()[\]\.,;:\s@\”]+(\.[^<>()[\]\.,;:\s@\”]+)*)|(\”.+\”))@(([^<>()[\]\.,;:\s@\”]+\.)+[^<>()[\]\.,;:\s@\”]{2,})$/i; But keep in mind that one should not rely … Read more
UPDATES http://so.lucafilosofi.com/jquery-validate-e-mail-address-regex/ using new regex added support for Address tags (+ sign) function isValidEmailAddress(emailAddress) { var pattern = /^([a-z\d!#$%&’*+\-\/=?^_`{|}~\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]+(\.[a-z\d!#$%&’*+\-\/=?^_`{|}~\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]+)*|”((([ \t]*\r\n)?[ \t]+)?([\x01-\x08\x0b\x0c\x0e-\x1f\x7f\x21\x23-\x5b\x5d-\x7e\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]|\\[\x01-\x09\x0b\x0c\x0d-\x7f\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))*(([ \t]*\r\n)?[ \t]+)?”)@(([a-z\d\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]|[a-z\d\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF][a-z\d\-._~\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]*[a-z\d\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])\.)+([a-z\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]|[a-z\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF][a-z\d\-._~\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]*[a-z\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])\.?$/i; return pattern.test(emailAddress); } if( !isValidEmailAddress( emailaddress ) ) { /* do stuff here */ } NOTE: keep in mind that no 100% regex email check exists!
What about this? bool IsValidEmail(string email) { var trimmedEmail = email.Trim(); if (trimmedEmail.EndsWith(“.”)) { return false; // suggested by @TK-421 } try { var addr = new System.Net.Mail.MailAddress(email); return addr.Address == trimmedEmail; } catch { return false; } } Per Stuart’s comment, this compares the final address with the original string instead of always returning … Read more
There is no point. Even if you can verify that the email address is syntactically valid, you’ll still need to check that it was not mistyped, and that it actually goes to the person you think it does. The only way to do that is to send them an email and have them click a … Read more
Another option is the built in Patterns starting with API Level 8: public final static boolean isValidEmail(CharSequence target) { if (TextUtils.isEmpty(target)) { return false; } else { return android.util.Patterns.EMAIL_ADDRESS.matcher(target).matches(); } } Patterns viewable source OR One line solution from @AdamvandenHoven: public final static boolean isValidEmail(CharSequence target) { return !TextUtils.isEmpty(target) && android.util.Patterns.EMAIL_ADDRESS.matcher(target).matches(); }
You can use the filter_var() function, which gives you a lot of handy validation and sanitization options. filter_var($email, FILTER_VALIDATE_EMAIL) PHP Manual filter_var() Available in PHP >= 5.2.0 If you don’t want to change your code that relied on your function, just do: function isValidEmail($email){ return filter_var($email, FILTER_VALIDATE_EMAIL) !== false; } Note: For other uses (where … Read more
There are two methods you can sometimes use to determine if a recipient actually exists: You can connect to the server, and issue a VRFY command. Very few servers support this command, but it is intended for exactly this. If the server responds with a 2.0.0 DSN, the user exists. VRFY user You can issue … Read more
See RFC 5322: Internet Message Format and, to a lesser extent, RFC 5321: Simple Mail Transfer Protocol. RFC 822 also covers email addresses, but it deals mostly with its structure: addr-spec = local-part “@” domain ; global address local-part = word *(“.” word) ; uninterpreted ; case-preserved domain = sub-domain *(“.” sub-domain) sub-domain = domain-ref … Read more
The easiest and safest way to check whether an email address is well-formed is to use the filter_var() function: if (!filter_var($email, FILTER_VALIDATE_EMAIL)) { // invalid emailaddress } Additionally you can check whether the domain defines an MX record: if (!checkdnsrr($domain, ‘MX’)) { // domain is not valid } But this still doesn’t guarantee that the … Read more