RegEx for jQuery Input Validation

Question

I am using jquery validation plugin for validating my input fields.

I have a field that should accept:

a) letters [a-zA-Z]

b) letters with numbers [a-zA-Z0-9]

c) no special characters

So:

ADFad1334 or 43545SFDDFdf454fgf : is correct, since we have letters and numbers

asdadadASD : is correct, since we have only letters

12312342 : NOT correct, since its only numbers

sdff23424#$ : NOT correct, since there are special characters (in this example # and $)

The code i used is the one below:

$.validator.addMethod("atLeastAletter", function(value) {
 return     /^[a-zA-Z]*$/img.test(value) || /^[a-zA-Z0-9]*$/img.test(value); 

},"Must contain at least a letter and/or number(s). No other characters are allowed");

And then:

$('#RegistrationForm').validate({

    rules:  {
                fieldname:  {
                                atLeastAletter: true

                            },

             .....

The problem with this regular expression is that if the input is only numbers (ex. 3434224), it will accept it and pass validation.

What is the problem?

Thanks in advance.

alpha bravo · Accepted Answer · 2014-11-21 22:05:00Z

2

or this pattern

^(?=\S*[a-zA-Z])[a-zA-Z0-9]+$

Demo

^               # Start of string/line
(?=             # Look-Ahead
  \S            # <not a whitespace character>
  *             # (zero or more)(greedy)
  [a-zA-Z]      # Character Class [a-zA-Z]
)               # End of Look-Ahead
[a-zA-Z0-9]     # Character Class [a-zA-Z0-9]
+               # (one or more)(greedy)
$               # End of string/line

answered Nov 21, 2014 at 22:05

alpha bravo

7,9681 gold badge24 silver badges25 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

AndrewTet · Accepted Answer · 2014-11-21 22:13:31Z

2

/^\w*[a-zA-Z]+\w*$/

That should match any string with only letters and numbers, but it must contain at least one letter.

sadAddsa  // Pass
98463298  // Fail
jdsH98sd  // Pass
987Fkjd89  // Pass
jfk!jhj  // Fail
kjhgh8768!@  // Fail
A8  // Pass
8S  // Pass
B  // Pass
7  // Fail
B_bkfd86jh // Fail (Using the regex in the edit)

Edit: As Alpha Bravo pointed out. This will match underscores too. If you don't want underscores /^[a-zA-Z0-9]*[a-zA-Z]+[a-zA-Z0-9]*$/will only match letters and numbers, only if it contains one letter.

edited Nov 21, 2014 at 22:13

answered Nov 21, 2014 at 22:04

AndrewTet

1,1828 silver badges22 bronze badges

3 Comments

alpha bravo Over a year ago

FYI, this pattern will match _ not sure if OK with OP!

AndrewTet Over a year ago

Ah, good catch. I've added an update that won't allow underscores.

christostsang Over a year ago

Andrew thanks for the answer, the second part works correctly, but alpha bravo did it first, so i accepted his answer. Thanks anyway.

Travis Pettry · Accepted Answer · 2014-11-21 21:55:01Z

If you want want to go with all HTML5 look at this fiddle: http://jsfiddle.net/bud68oho/2/

This fiddle uses the required and pattern attributes to validate the form. The required attribute does not allow the form to post if the input is not filled in. The pattern attribute allows you to implement regex for matching. If the input does not meet the requirements of the regex then the form will not post.

The only gotcha with this approach is browser compatibility. Make sure to test this method with your target browsers. The above example works in the latest version of IE and Chrome, I am unable to do any further testing.

KyleK · Accepted Answer · 2014-11-21 22:00:53Z

/^[a-zA-Z0-9]*$/img.test("1") is true, so just take with two regexp for both:

return /^[a-zA-Z]*$/img.test(value) || (/[a-zA-Z]/img.test(value) && /^[a-zA-Z0-9]*$/img.test(value))

or like this:

return /^[a-zA-Z]*$/img.test(value) || (/^[a-zA-Z0-9]*$/img.test(value) && !/^[0-9]*$/img.test(value))

Notice: If you put i after the regexp (img) you just have to put a-z or A-Z, it's not case sensitive. Ohter notice: you allow empty strings "" with those regexps.

Lee Jenkins · Accepted Answer · 2014-11-21 22:01:12Z

0

I think you may need to do a positive alphanumeric check and a negative check for the numeric only case.

$.validator.addMethod("atLeastAletter", function(value) {
  return     /^[a-zA-Z0-9]+$/img.test(value) && ! /^[0-9]+$/img.test(value)

},"Must contain at least a letter and/or number(s). No other characters are allowed");

answered Nov 21, 2014 at 22:01

Lee Jenkins

2,4903 gold badges27 silver badges42 bronze badges

Collectives™ on Stack Overflow

RegEx for jQuery Input Validation

5 Answers 5

Comments

3 Comments

Comments

Comments

Comments

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

Comments

3 Comments

Comments

Comments

Comments

Related