JS makes verification email/email address regular

This time I will bring you JS to make a regular verification email/email address. What are the precautions for using JS to make a regular verification email/email address? The following is a practical case, let's take a look.

The rules are defined as follows:

• Use uppercase letters [A-Z], lowercase letters [a-z], numbers [0-9], underline [_], and minus sign It starts with [-] and a period [.], and needs to be repeated one or more times [ ].

• The @ symbol must be included in the middle.

• @After that, you need to connect uppercase letters [A-Z], lowercase letters [a-z], numbers [0-9], underscore [_], minus sign [-] and dot [ .], and needs to be repeated one or more times [ ].

• must end with a period [.] connecting 2 to 4 digits of uppercase and lowercase letters [A-Za-z]{2,4}.

Use the above rules to give the following regular expression:

var pattern = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;

Complete test code

nbsp;HTML>


  <meta>
  <title>邮箱/邮件地址的正则表达式及分析(JavaScript，email，regex)</title>


<p></p>
<script>
  var pattern = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
  w("pattern.test(&#39;cn42du@163.com&#39;) = "+pattern.test(&#39;cn42du@163.com&#39;)+";");
  w("pattern.test(&#39;ifat3@sina.com.cn&#39;) = "+pattern.test(&#39;ifat3@sina.com.cn&#39;)+";");
  w("pattern.test(&#39;ifat3.it@163.com&#39;) = "+pattern.test(&#39;ifat3.it@163.com&#39;)+";");
  w("pattern.test(&#39;ifat3_-.@42du.cn&#39;) = "+pattern.test(&#39;ifat3_-.@42du.cn&#39;)+";");
  w("pattern.test(&#39;ifat3@42du.online&#39;) = "+pattern.test(&#39;ifat3@42du.online&#39;)+";");
  w("pattern.test(&#39;毛三胖@42du.cn&#39;) = "+pattern.test(&#39;毛三胖@42du.cn&#39;)+";");
  function w(val) {
    document.getElementById("main").innerHTML += val +"<br />";
  }
</script>

Test result:

pattern.test('cn42du@163.com') = true;
pattern.test('ifat3@sina.com.cn') = true;
pattern.test('ifat3.it@163. com') = true;
pattern.test('ifat3_-.@42du.cn') = true;
pattern.test('ifat3@42du.online') = false;
pattern.test ('Mao Sanpang@42du.cn') = false;
pattern.test('cn42du@163.com') = true;
pattern.test('ifat3@sina.com.cn') = true;
pattern.test('ifat3.it@163.com') = true;
pattern.test('ifat3_-.@42du.cn') = true;
pattern.test(' ifat3@42du.online') = false;
pattern.test('Mao Sanpang@42du.cn') = false;

Description of Plan 1

Scheme 1 is the most commonly used email regular expression verification scheme and is suitable for most application scenarios. As can be seen from the above test, this expression does not support domain names ending in .online and .store. If you need to be compatible with this type of domain name (more than 4 digits), just adjust the restriction part at the end of the regular expression {2,4} (for example: {2,8}). Another problem is that email usernames cannot include Chinese characters.

Option 2 (revised option 1)

The rules are supplemented as follows:

• The user name can include Chinese [\u4e00- \u9fa5]

• The end of the domain name can be up to 8 digits{2,8}

• The updated regular expression is as follows:

var pattern = /^([A-Za-z0-9_\-\.\u4e00-\u9fa5])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,8})$/;

Complete test code

nbsp;HTML>


  <meta>
  <title>邮箱/邮件地址的正则表达式及分析(JavaScript，email，regex)</title>


<p></p>
<script>
  var pattern = /^([A-Za-z0-9_\-\.\u4e00-\u9fa5])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,8})$/;
  w("pattern.test(&#39;cn42du@163.com&#39;) = "+pattern.test(&#39;cn42du@163.com&#39;)+";");
  w("pattern.test(&#39;ifat3@sina.com.cn&#39;) = "+pattern.test(&#39;ifat3@sina.com.cn&#39;)+";");
  w("pattern.test(&#39;ifat3.it@163.com&#39;) = "+pattern.test(&#39;ifat3.it@163.com&#39;)+";");
  w("pattern.test(&#39;ifat3_-.@42du.cn&#39;) = "+pattern.test(&#39;ifat3_-.@42du.cn&#39;)+";");
  w("pattern.test(&#39;ifat3@42du.online&#39;) = "+pattern.test(&#39;ifat3@42du.online&#39;)+";");
  w("pattern.test(&#39;毛三胖@42du.cn&#39;) = "+pattern.test(&#39;毛三胖@42du.cn&#39;)+";");
  function w(val) {
    document.getElementById("main").innerHTML += val +"<br />";
  }
</script>

Test result:

##pattern.test('cn42du@163.com') = true;

pattern.test('ifat3@sina.com.cn') = true;
pattern.test('ifat3.it@163.com') = true;
pattern.test('ifat3_-.@ 42du.cn') = true;
pattern.test('ifat3@42du.online') = true;
pattern.test('Mao Sanpang@42du.cn') = true;

Option 3 (Security)

Before the mobile phone verification code appeared, email verification was almost the only condition to ensure the uniqueness of the user. The emergence of temporary mailboxes (also called 10-minute mailboxes or disposable mailboxes) makes the mechanism of mailbox verification and account activation meaningless. The addresses of temporary email addresses are not enumerable. We can only use a whitelist to allow only a limited number of email domain names to pass verification.

According to the following supplementary rules for option 1:

The email domain name can only be 163.com, qq.com or 42du.cn.

The regular expression is given as follows:

var pattern = /^([A-Za-z0-9_\-\.])+\@(163.com|qq.com|42du.cn)$/;

Complete test code

nbsp;HTML>


  <meta>
  <title>邮箱/邮件地址的正则表达式及分析(JavaScript，email，regex)</title>


<p></p>
<script>
  var pattern = /^([A-Za-z0-9_\-\.])+\@(163.com|qq.com|42du.cn)$/;
  w("pattern.test(&#39;cn42du@163.com&#39;) = "+pattern.test(&#39;cn42du@163.com&#39;)+";");
  w("pattern.test(&#39;ifat3@sina.com.cn&#39;) = "+pattern.test(&#39;ifat3@sina.com.cn&#39;)+";");
  w("pattern.test(&#39;ifat3.it@163.com&#39;) = "+pattern.test(&#39;ifat3.it@163.com&#39;)+";");
  w("pattern.test(&#39;ifat3_-.@42du.cn&#39;) = "+pattern.test(&#39;ifat3_-.@42du.cn&#39;)+";");
  w("pattern.test(&#39;ifat3@42du.online&#39;) = "+pattern.test(&#39;ifat3@42du.online&#39;)+";");
  w("pattern.test(&#39;毛三胖dd@42du.cn&#39;) = "+pattern.test(&#39;毛三胖@42du.cn&#39;)+";");
  function w(val) {
    document.getElementById("main").innerHTML += val +"<br />";
  }
</script>

Test result:

pattern.test('cn42du@163.com') = true;
pattern.test('ifat3@sina.com.cn') = false;
pattern.test('ifat3.it@163.com') = true;
pattern.test('ifat3_-.@42du.cn') = true;
pattern.test('ifat3@42du.online') = false;
pattern.test('毛三胖dd@42du.cn') = false;

Although scheme 3 verification can ensure security, if the whitelist Too long will cause the pattern string to be too long. At this time, you can write the email domain name whitelist as an array, use regular expressions for preliminary verification, and use the whitelist for secondary verification of the domain name.

The email verification function is now given as follows:

var isEmail = function (val) {
  var pattern = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
  var domains= ["qq.com","163.com","vip.163.com","263.net","yeah.net","sohu.com","sina.cn","sina.com","eyou.com","gmail.com","hotmail.com","42du.cn"];
  if(pattern.test(val)) {
    var domain = val.substring(val.indexOf("@")+1);
    for(var i = 0; iThe above isEmail() function lists 11 commonly used email domain names. You can add or delete them as needed. <p style="text-align: left;"></p> I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website! <p></p>Recommended reading: <p></p><p>302 status code in axios<a href="http://www.php.cn/js-tutorial-402085.html" target="_blank"></a><br></p><p>Encapsulate Vue2 routing navigation hook and use it in actual combat<a href="http://www.php.cn/js-tutorial-402104.html" target="_blank"></a><br></p>

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