JavaScript Regular Expression Match
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The document provides a comprehensive overview of using regular expressions in JavaScript for various types of validation, including string matching, mobile number checks, and email format verification. It details specific patterns for matching characters, lengths, and formats, such as validating a five-digit PIN, a ten-digit mobile number, and a structured email address. Examples and explanations of the regex syntax are included to assist in understanding the concepts presented.
![Let’s see some basic notes:
1. Regular Expression must be written between / /;
Example: /road2code/;
It will find match for road2code in string.
2. [abc] it will find match for any character present in [ ].
Example: /[abc123]/;
It will accept single a, single b or single 1,2,3
It will only specify one-character matching
3. Allow all character from a-z (upper case + lower case)
Example: /[a-zA-Z]/;
It will accept any alphabet from a-z (upper case+lower
case)
4. All character Except Some character
Example: /[^ab]/;
It will accept c-z not a and b
Example: /[^rs]000/;
It will not accept r000 or s000 it will accept a000 or b000
and so on.
5. Allow word with 5 character only
Example: /[a-zA-Z]{5}/;
It will accept Hello
It will not accept aHello
6. Allow only 5digits (Pin code validation)
Example: /[0-9]{5}/;](https://image.slidesharecdn.com/validationusingregularexpression1-180504072121/85/JavaScript-Regular-Expression-Match-2-320.jpg)
![Need to know
w: [a-zA-z0-9_] (character+digits+_)
s: White space, tabs
t: tab
d: digits [0-9]
+ : 1 or more occurrence
? : 0 or more occurrence
[] : Character Set
[^]: exclude character set
: escape character](https://image.slidesharecdn.com/validationusingregularexpression1-180504072121/85/JavaScript-Regular-Expression-Match-4-320.jpg)
![1)Mobile Number Validation: (10 digits only)
Expression: /^[0-9]{10}$/;
Examples:
1.1234567895 Accepted
2.12asdfa257 Rejected
3.123456789798 Rejected
Instead of writing [0-9] every time we can write d also.
Expression for Mobile validation: /^d{10}$/;
2)Pin Code Validation: (5digits only)
Expression: /^[0-9]{5}$/;
Examples:
1.360005 Accepted
2.12asdfa257 Rejected
3.abcdefg Rejected](https://image.slidesharecdn.com/validationusingregularexpression1-180504072121/85/JavaScript-Regular-Expression-Match-5-320.jpg)
![Email id Validation:
Email id consist of:
(name) @ (domain_name) . (com/co/net) . (in/uk/au)
Example: upadhyayraj007@gmail.com
Here
Name = upadhyayraj007
@
Domain_name = gmail
.
Extension = com
So now let’s build this one by one
1)Name
It may have alphabets digits or ‘.’ Or ‘-‘
So for this Expression:
/^[a-zA-Zd.-]+$/;
So it means One or more occurrence of a-z or 0-9 or . or -
2)@
Expression: /^[a-zA-Zd.-]+@$/;
3)(domain name)
Expression: ([a-zd.-]+)
Combine with first two expressions:
/^[a-zA-Zd.-]+@([a-zd.-]+)$/;](https://image.slidesharecdn.com/validationusingregularexpression1-180504072121/85/JavaScript-Regular-Expression-Match-6-320.jpg)
![4) .
Expression: .
Up to this:
/^[a-zA-Zd.-]+@([a-zd.-]+).$/;
5) (com,net,co…etc)
Expression: ([a-z]{2,8})
There must be at least 2 character and maximum 8 charater.
Expression : /^([a-zd.-]+)@([a-zd.-]+).([a-z]{2,8})$/;
6) optional (.uk,.in,.au…etc)
Expression: (.[a-z]{2,8})?
There must be . then some character but min length 2 and
max length 8 and we put ? in last because it’s option many of
us don’t have such email id like admin@road2code.co.in
Final Expression:
Expression: /^([a-zd.-]+)@([a-zd.-]+).([a-z]{2,8})(.[a-z]{2,8})?$/;](https://image.slidesharecdn.com/validationusingregularexpression1-180504072121/85/JavaScript-Regular-Expression-Match-7-320.jpg)
![HTML CODE for Email validation
<html>
<body>
<form name="registration" method="POST" onSubmit="return form1()">
<input type="text" name="email">
<input type="submit" value="login">
</form>
<script>
function form1(){
var email=document.registration.email.value;
var email_chk=emailchk(email);
if(email_chk==false){
alert("Invalid Email id");
}
else{
alert("valid Email id");
}
}
function emailchk(em){
var pattern1=/^([a-zd.-]+)@([a-zd.-]+).([a-z]{2,8})(.[a-z]{2,8})?$/;
var match1=new RegExp(pattern1);
return match1.test(em);
}
</script>
</body>
</html>](https://image.slidesharecdn.com/validationusingregularexpression1-180504072121/85/JavaScript-Regular-Expression-Match-8-320.jpg)
JavaScript Regular Expression Match
- 1. Validation using Regular Expression (JS)
- 2. Let’s see some basic notes: 1. Regular Expression must be written between / /; Example: /road2code/; It will find match for road2code in string. 2. [abc] it will find match for any character present in [ ]. Example: /[abc123]/; It will accept single a, single b or single 1,2,3 It will only specify one-character matching 3. Allow all character from a-z (upper case + lower case) Example: /[a-zA-Z]/; It will accept any alphabet from a-z (upper case+lower case) 4. All character Except Some character Example: /[^ab]/; It will accept c-z not a and b Example: /[^rs]000/; It will not accept r000 or s000 it will accept a000 or b000 and so on. 5. Allow word with 5 character only Example: /[a-zA-Z]{5}/; It will accept Hello It will not accept aHello 6. Allow only 5digits (Pin code validation) Example: /[0-9]{5}/;
- 3. It will accept: 360005 It will not accept: 25684572 7. Must Start with Alphabet ‘a’: Example:/^a/; It will accept: abcasadf It will not accept:bcadae 8. Must End with Alphabet ‘a’: Example:/a$/; It will accept: abcderfga It will not accept: abcdefg 9. Must be a “Hello” word: Example: /^Hello$/; It will accept: Hello It will not accept: hello
- 4. Need to know w: [a-zA-z0-9_] (character+digits+_) s: White space, tabs t: tab d: digits [0-9] + : 1 or more occurrence ? : 0 or more occurrence [] : Character Set [^]: exclude character set : escape character
- 5. 1)Mobile Number Validation: (10 digits only) Expression: /^[0-9]{10}$/; Examples: 1.1234567895 Accepted 2.12asdfa257 Rejected 3.123456789798 Rejected Instead of writing [0-9] every time we can write d also. Expression for Mobile validation: /^d{10}$/; 2)Pin Code Validation: (5digits only) Expression: /^[0-9]{5}$/; Examples: 1.360005 Accepted 2.12asdfa257 Rejected 3.abcdefg Rejected
- 6. Email id Validation: Email id consist of: (name) @ (domain_name) . (com/co/net) . (in/uk/au) Example: upadhyayraj007@gmail.com Here Name = upadhyayraj007 @ Domain_name = gmail . Extension = com So now let’s build this one by one 1)Name It may have alphabets digits or ‘.’ Or ‘-‘ So for this Expression: /^[a-zA-Zd.-]+$/; So it means One or more occurrence of a-z or 0-9 or . or - 2)@ Expression: /^[a-zA-Zd.-]+@$/; 3)(domain name) Expression: ([a-zd.-]+) Combine with first two expressions: /^[a-zA-Zd.-]+@([a-zd.-]+)$/;
- 7. 4) . Expression: . Up to this: /^[a-zA-Zd.-]+@([a-zd.-]+).$/; 5) (com,net,co…etc) Expression: ([a-z]{2,8}) There must be at least 2 character and maximum 8 charater. Expression : /^([a-zd.-]+)@([a-zd.-]+).([a-z]{2,8})$/; 6) optional (.uk,.in,.au…etc) Expression: (.[a-z]{2,8})? There must be . then some character but min length 2 and max length 8 and we put ? in last because it’s option many of us don’t have such email id like admin@road2code.co.in Final Expression: Expression: /^([a-zd.-]+)@([a-zd.-]+).([a-z]{2,8})(.[a-z]{2,8})?$/;
- 8. HTML CODE for Email validation <html> <body> <form name="registration" method="POST" onSubmit="return form1()"> <input type="text" name="email"> <input type="submit" value="login"> </form> <script> function form1(){ var email=document.registration.email.value; var email_chk=emailchk(email); if(email_chk==false){ alert("Invalid Email id"); } else{ alert("valid Email id"); } } function emailchk(em){ var pattern1=/^([a-zd.-]+)@([a-zd.-]+).([a-z]{2,8})(.[a-z]{2,8})?$/; var match1=new RegExp(pattern1); return match1.test(em); } </script> </body> </html>