USEFUL REGULAR EXPRESSIONS

In Web Development, there have forms we need to secure and validate using Regular Expression, in some cases are registration form, transaction forms such as valid email, valid postal code, matching strong password and securities.

In this article, i have compiled the useful of JavaScript Regular Expression, this is the most common regular expression we use in web development such validating forms. These Regular Expression will not match in common cases, it even fewer special cases you might be need, because any Regular Expression can be written broadly and narrowly, meaning, broadly is a match a lot of pattern and narrowly is very restricted in matching.

1. Matching names

Regex:

1	/^([A-Z][A-Za-z.'\- ]+) (?:([A-Z][A-Za-z.'\-]+) )?([A-Z][A-Za-z.'\-]+)$/

String that matches:

1

John Doe

2	John de Doe

3	John Doe Doe

4	John Doe D. Doe J.r III

Pattern can match any valid names with first character capitalize.

2. Matching postal codes

Regex:

1	/^\d{4,5}(?:-\d{4,5})?$/

String that matches:

1

75087

2	10010-6543

Pattern can match postal codes broadly, they match mostly US postal code.

3. Matching email addresses

Regex:

1	/^[\w%_\-.\d]+@[\w.\-]+.[A-Za-z]{2,6}$/

String that matches:

1	someone@istockphp.com

2	someone@istockphp.co.uk

3	someone@istockphp.net

4	some-one@istockphp.edu

Pattern can match any valid email format, however this is most common use for validating email in registration form.

4. Matching urls

Regex:

1	/^(http|https):\/\/[\w.\-]+(\.[\w\-]+)+[/#?\w\-.,@?^=&%:;/~\\+#]+$/

String that matches:

1	http://www.istockphp.com

2

3

4	http://istockphp.com

5

6

7	http://blog.istockphp.com

8

9

10	https://www.istockphp.com

11

12

13	http://www.istockphp.com/product_page.html

14

15

16	http://www.istockphp.com/images/image.gif

17

18

19	http://www.istockphp.com/product/

20

21

22	http://www.istockphp.com/product/3456

23

24

25	http://www.istockphp.com/product_page.php?product=28

26

27

28	http://www.istockphp.com?product=28&color=blue

29

30

31	http://www.istockphp.com#details

32

33

34	http://255.255.255.255

In the form, might have a extra field to input the user for URL, this regex validate the valid url.

5. Matching decimal numbers

Regex:

1	/^(\d*\.\d+|\d+)$/

String that matches:

1

5.4

2

314.35634

3

0.123

4

.345

5

25

Pattern match a valid decimal numbers.

5. Matching currencies

Regex:

1	/^(\$|£|¥)(\d*\.\d+|\d+)$/

String that matches:

1

$50

2

$43.23

3

$0.39

4

$.60

5

£498.10

6

¥12

Pattern can match the right currencies, in reg ex you can add more currencies to match.

6. Matching ip addresses

Regex:

1	/^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/

String that matches:

1	255.255.255.255

2

0.0.0.0

3	67.52.159.38

4	067.052.159.038

Pattern can match the right ip address, obviously the ip address ’999.999.999.999′ will not match.

7. Matching dates

Regex:

1	/^\d{1,4}[-/](0?[1-9]|1[0-2])[-/](0?[1-9]|[12][0-9]|3[01])$/

String that matches:

1	2000-11-15

2

2000-6-9

3	2000-06-09

4

2000/6/9

Pattern can matches the date format, year, month and day.

8. Matching time in 12hrs

Regex:

1	/^(0?[1-9]|1[0-2]):[0-5][0-9]([aApP][mM])?/

String that matches:

1

02:34

2

2:34pm

3

2:34PM

4

02:34

5

12:34

6

12:59

7

1:00PM

Pattern can match 12 hrs time. it match up to 12:59 am and pm.

9. Matching time in 24hrs with Time zone

Regex:

1	/^([0-1]?[0-9]|2[0-3]):[0-5][0-9](:[0-5][0-9])?( ([A-Z]{3}|GMT [-+]([0-9]|1[0-2])))?$/

String that matches:

1

0:02

2

2:34

3

02:34

4

12:34

5

12:34:56

6

12:34 EST

7	12:34 GMT -5

8	12:34 GMT +12

9

23:45

Pattern can match 24 hrs time. it match up to 23:59 including timezone.

10. Matching HTML tags

Regex:

1	/^<(?:([A-Za-z][A-Za-z0-9]*)\b[^>]*>(?:.*?)|[A-Za-z][A-Za-z0-9]*\b[^/>]*/>)$/

String that matches:

1	<strong>Bold</strong>

2	<em>Emphazied</em>

3	<b>Bold</b>

4	<i>Italics</i>

5	<span id="foo">this is the text</span></pre>

6

7

<hr />

8

9

<pre>

10	<strong>Bold</strong>

11	<em>Emphazied</em>

12	<b>Bold</b>

13	<i>Italics</i>

14	<span id="foo">this is the text</span></pre>

15

16

<hr />

17

18

<pre>

Pattern can match HTML tags.

11. Validating strong passwords

Regex:

1	/^(?=.*\d)(?=.*[~!@#$%^&*()_\-+=|\\{}[\]:;<>?/])(?=.*[A-Za-z])(?=.*[a-z])\S{8,15}$/

String that matches:

1	mypassword69[]

2	mypass';i#%^9[]

This pattern help to make sure user give a secure password that’s harder for hacker to crack it.

Pattern for password requires.

• Password Any character, except space.
• Password at least 8 characters long
• And not more than 15 characters.
• Password must have a number.
• Password must have a special character.

12. Matching credit card numbers

Regex:

1	/^(?:3[47]\d{2}([\- ]?)\d{6}\1\d{5}|(?:4\d{3}|5[1-5]\d{2}|6011)([\- ]?)\d{4}\2\d{4}\2\d{4})$/

String that matches:

1	American Express

2	370012345612345

3	3700 123456 12345

4	3700-123456-12345

5

6

Visa

7	4000123412341234

8	4000 1234 1234 1234

9	4000-1234-1234-1234

10

11	Mastercard

12	5100123412341234

13	5100 1234 1234 1234

14	5100-1234-1234-1234

15

16

Discover

17	6011123412341234

18	6011 1234 1234 1234

19	6011-1234-1234-1234

Pattern can match 4 major of credit card numbers, American Express, Visa, MasterCard, Discover.