I'm trying to use regex to validate a telephone number in javascript

Question

I'm trying to figure out why this doesn't work. I need to validate a telephone number in a form and my research show that this should work for a north American telephone number format.

I had /g at the end but that still didn't work...correctly formatted input is still false.

I used https://regex101.com/ and it looks like it is correct!

<!DOCTYPE html>
<html lang="en-US">

<head>
</head>

<body>  
    <section>
        <form>        
            <label for="phoneNumber">Phone Number
            </label>
            <input type="text" name="telephone" placeholder="Enter your Phone Number" />
        </form>
    </section>

let telInput = form.querySelector("[name='telephone']"),
    tel = telInput.value;
//regex solution:
regex = /\([0-9]{3}\)\n[0-9]{3}-[0-9]{4}/;
if (!regex.test(tel)) {
        alert("You have to use (xxx) xxx-xxxx format.");
    telInput.focus();
        return;
    }

Possible duplicate of [A comprehensive regex for phone number validation](https://stackoverflow.com/questions/123559/a-comprehensive-regex-for-phone-number-validation) — imjared, Aug 26 '19 at 14:37
replace the `\n` with a space and you also might use anchors `^` and `$` — The fourth bird, Aug 26 '19 at 14:37
`\n` is a newline, `input` element does not allow entering newlines. Replace `\n` with `\s` or `\s*`, and yes, add anchors: `regex = /^$[0-9]{3}$\s[0-9]{3}-[0-9]{4}$/;` or `regex = /^$[0-9]{3}$\s*[0-9]{3}-[0-9]{4}$/;` — Wiktor Stribiżew, Aug 26 '19 at 14:42

Nick Reed · Accepted Answer · 2019-08-26T14:50:05.423

1

Your regex is very close! Try replacing \n (newline) with (space literal). Adding anchors ^$ also helps you avoid partial matches.

^$[0-9]{3}$ [0-9]{3}-[0-9]{4}$

Try it here!

edited Aug 26 '19 at 14:50

answered Aug 26 '19 at 14:45

Nick Reed

4,989
4
17
37

I'm trying to use regex to validate a telephone number in javascript

1 Answers1