Home > Others

JS Email e-mail address verification Program

Source: Internet
Author: User
Tags chr
Developer on Alibaba Coud: Build your first app with APIs, SDKs, and tutorials on the Alibaba Cloud. Read more ＞

The original code is like this:

The code is as follows Copy Code

function Isvalidmail (stext) {
var reMail =/^ (?: w+.?) *w+@ (?: w+.?) *w+$/;
Return Remail.test (stext);
}

Seems

This verifies that mailboxes like sofish@163.com are fine. However, with a closer look at the non-capture reference after at (@), you are using * (any occurrence):

The code is as follows Copy Code

var reMail =/^ (?: w+.?) *w+@ (?: w+.?) *w+$/;

Well, it also includes 0 times, so to say. Mailboxes such as sofish@163com are also validated. Obviously, "." Must occur at least once, and therefore "+" does not represent at least one occurrence. But here, at the back of the AT, we can write the end like 163.com.cn, but directly to "+", so that 163..com.cn can also pass the verification. Here is my method:

The code is as follows Copy Code
function Isvalidmail (stext) {
var reMail =/^ (?: w+.?) *w+@ (?: w+.) +w+$/;
Alert (Remail.test (stext))
}

Rules "." Number appears only once. Then, after the non capture reference, let the other display at least 1 times, and then end with any character. However, the "W" here is underlined, that is to say, mail like Sofish@163_.com_ is also likely to pass through difficult, apparently, this is an illegal message, at the back of the "." Before, is not to be underlined, and the back, can only be English letters (at least for now I have not seen with the following is a number of domain names). And, what should be noted here is that the characters represented by "W" include underscores, without abbreviations:

[A-za-z_0-9] Therefore, the above code can be modified in this way:

The code is as follows Copy Code

function Isvalidmail (stext) {
var reMail =/^ (?: [a-zd]+[_-+.]?) *[a-zd]+@ (?:( [a-zd]+-?] *[a-zd]+.) + ([A-z]{2,}) +$/i;
Alert (Remail.test (stext))
}

Instance

The code is as follows Copy Code

<script>
function Validate ()
{
var pattern=/^w+ ([-+.] w+) *@w+ ([-.] w+) *.w+ ([-.] w+) *$/;
var email = document.getElementById ("Mail"). Value;

if (!pattern.test (email))
Alert ("wrong");
Else
Alert (' Right ')
}
</script>

<input type= "text" name= "Mail" id= "Mail" >
<input type= "button" value= "onclick=" Validate () ">

Name= "Mail" id= "Mail" ><input type= "button" value= "" onclick= "Validate ()" >

JavaScript Verify mailbox format

The code is as follows Copy Code
<script Language=javascript runat=server>
function Isemail (stremail) {
if (/^w+ (-w+) | (stremail.search) | (. w+)) *@[a-za-z0-9]+ ((. | -) [a-za-z0-9]+] *. [a-za-z0-9]+$/)!=-1)
return true;
Else
Alert ("Oh");
}
</SCRIPT>
<input type=text onblur=isemail (this.value) >

Second: Use JavaScript to verify that email is correctly filled in

  code is as follows copy code

<title>test</title>
< Script language= "javascript"
function Emailcheck () {
var emailstr=document.all.form1.tel.value;
Alert (EMAILSTR);
var emailpat=/^ (. +) @ (. +) $/;
var matcharray=emailstr.match (Emailpat);
if (matcharray==null) {
Alert ("E-mail address must include (@ and.)")
return false;
}
return true;
}
</script>

<body>
<form name= "Form1"
<input type= "text" Name= "Tel"/>
<input type= "button" value= "Press" onclick= "Emailcheck ()"/>
</form>


</span>
</body>

The third type:

The code is as follows Copy Code

JS Verification Email
function Char_test (CHR)
Character detection function
{
var i;
var smallch= "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
var bigch= "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
for (i=0;i<26;i++)
if (Chr==smallch.charat (i) | | Chr==bigch.charat (i))
return (1);
return (0);
}

function Spchar_test (CHR)
Digital and special character detection functions
{
var i;
var spch= "_-.0123456789";
for (i=0;i<13;i++)
if (Chr==spch.charat (i))
return (1);
return (0);
}

function Email_test (str)
{
var i,flag=0;
var at_symbol=0;
Location of "@" detected
var dot_symbol=0;
“.” Location of the test
if (Char_test (Str.charat (0)) ==0)
return (1);
First character must be in letter

for (i=1;i<str.length;i++)
if (Str.charat (i) = = ' @ ')
{
At_symbol=i;
Break
}
Detect the location of "@"

if (at_symbol==str.length-1 | | at_symbol==0)
return (2);
No mail server domain name

if (at_symbol<3)
return (3);
Account number is less than three characters

if (at_symbol>19)
return (4);
Account number is more than 19 characters

for (i=1;i<at_symbol;i++)
if (Char_test (Str.charat (i)) ==0 && spchar_test (Str.charat (i)) ==0)
return (5);
for (i=at_symbol+1;i<str.length;i++)
if (Char_test (Str.charat (i)) ==0 && spchar_test (Str.charat (i)) ==0)
return (5);
Cannot use other special characters

for (i=at_symbol+1;i<str.length;i++)
if (Str.charat (i) = = '. ') dot_symbol=i;
for (i=at_symbol+1;i<str.length;i++)
if (dot_symbol==0 | | dot_symbol==str.length-1)
Simple detection has no "." To determine whether the server name is legitimate
return (6);

return (0);
Mail name Legal
}

Add to the Knowledge

1. /^$/This is a generic format.
         ^ matches the start position of the input string; $ matches the end position of the input string
 2. Enter the function you want to implement.
        * matches the preceding subexpression 0 or more times;
       + Matches the preceding subexpression one or more times;
       Matches the preceding subexpression 0 times or once;
       d  matches a numeric character, equivalent to [0-9]

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

Related Keywords:
is email or e mail usps address verification database experian address verification sender address verification e911 address verification safelink address verification icloud verification email

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

What's Trending
Top 10 Tags
datastax versions naming convention zookeeper client class definition md5 microsoft sql server 2005 data structures exception handling error handling
Top 10 Keywords
microsoft download center down wordpress address url site address url wordpress address url windows installer 4 0 download 302 not found web address url definition site address url wordpress db2 integer mac os installation step by step pdf abbreviation for return

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

  • Sales Support

    1 on 1 presale consultation

    Chat Contact Sales

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

    Open a Ticket

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

    Learn More