alphanumeric regex javascript

Question

I am having a problem to get the simple reges for alphanumeric chars only work in javascript :

var validateCustomArea = function () {
        cString = customArea.val();
        var patt=/[0-9a-zA-Z]/;
        if(patt.test(cString)){
            console.log("valid");
        }else{
            console.log("invalid");
        }
    }

I am checking the text field value after keyup events from jquery but the results are not expected, I only want alphanumeric charachters to be in the string

I am guessing the regex above checks if in your string exists any, I want for my string to be only alphanumeric — Saher Ahwal
– Saher Ahwal, Commented Oct 31, 2011 at 4:05
@muistooshort Correct me if I'm wrong, but aren't they optional most of the time? Sometimes they are required, hence the good habit to always use them. — SeanCannon
– SeanCannon, Commented Oct 31, 2011 at 4:07

mu is too short · Accepted Answer · 2011-10-31 04:08:29Z

7

This regex:

/[0-9a-zA-Z]/

will match any string that contains at least one alphanumeric character. I think you're looking for this:

/^[0-9a-zA-Z]+$/
/^[0-9a-zA-Z]*$/ /* If you want to allow "empty" through */

Or possibly this:

var string = $.trim(customArea.val());
var patt   = /[^0-9a-z]/i;
if(patt.test(string))
    console.log('invalid');
else
    console.log('valid');

answered Oct 31, 2011 at 4:08

mu is too short

436k71 gold badges863 silver badges822 bronze badges

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

Comments

Jon Newmuis · Accepted Answer · 2011-10-31 04:08:44Z

2

Your function only checks one character (/[0-9a-zA-Z]/ means one character within any of the ranges 0-9, a-z, or A-Z), but reads in the whole input field text. You would need to either loop this or check all characters in the string by saying something like /^[0-9a-zA-Z]*$/. I suggest the latter.

answered Oct 31, 2011 at 4:08

Jon Newmuis

26.7k3 gold badges48 silver badges57 bronze badges

Comments

Saher Ahwal · Accepted Answer · 2011-10-31 04:14:00Z

2

I fixed it this way

var validateCustomArea = function () {
        cString = customArea.val();
        console.log(cString)
        var patt=/[^0-9a-zA-Z]/
        if(!cString.match(patt)){
            console.log("valid");
        }else{
            console.log("invalid");
        }
    }

I needed to negate the regex

answered Oct 31, 2011 at 4:14

Saher Ahwal

9,26733 gold badges91 silver badges156 bronze badges

Collectives™ on Stack Overflow

alphanumeric regex javascript

3 Answers 3

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related