Abhishek Gupta

The Sun won’t set at NIT Durgapur !

Archive for the ‘web’ Category

Regular Expressions in Javascript

Posted by abhiitechie on May 17, 2009

Here are some examples of using regular expressions for input validations in javascript.

var input = “hello222”;
var ok = false;

var dob_regex = /^([0-9]){2}(\/){1}([0-9]){2}(\/)([0-9]){4}$/;   // DD/MM/YYYY
var email_regex = /^[a-zA-Z0-9._-]+@([a-zA-Z0-9.-]+\.)+[a-zA-Z0-9.-]{2,4}$/;  // email address
var username_regex = /^[\w.-]+$/;  // allowed characters: any word . -, ( \w ) represents any word character (letters, digits, and the underscore _ ), equivalent to [a-zA-Z0-9_]
var num_regex = /^\d+$/; // numeric digits only
var search_regex = “/hello/”;
var password_regex = /^[A-Za-z\d]{6,8}$/;  // any upper/lowercase characters and digits, between 6 to 8 characters in total
var phone_regex = /^\(\d{3]\) \d{3}-\d{4}$/;  // (xxx) xxx-xxxx
var question_regex = /\?$/; // ends with a question mark

1. Check that there are at least 3 numeric characters in input
if ( input.match(/d/g) == null ) {
ok = false;
} else if ( input.match(/d/g).length < 3 )  {
ok = false;
} else {
ok = true;
}
2. Check that the input has a minimum of 8 characters
if ( input.length >= 8 ) {
ok = true;
}
3. Check that the input is in a correct date format (DD/MM/YYYY)
if ( dob_regex.test(input) ) {
ok = true;
}
4. Check that the input is in a correct email format (username@example.com)
if ( email_regex.test(input) ) {
ok = true;
}
5. Check that the input matches the specified username format
if ( username_regex.test(input) ) {
ok = true;
}
6. Check that the input contains only numeric characters
if ( input.match(num_regex) ) {
ok = true;
}
7. Search for a specific word in the input
if ( input.search(search_regex) != -1 ) {
ok = true;
}
8. Check that the input matches the specified password format
if ( input.match(password_regex) ) {
ok = true;
}
9. Check that the input matches the specified phone number format
if ( input.match(phone_regex) ) {
ok = true;
}
10. Check that the input is a question (ends with a question mark)
if ( question_regex.test(input) ) {
ok = true;
}

Posted in Personal, web | Tagged: , , , , | 6 Comments »