JavaScript test RegEx always returning false

Question

I'm trying to verify if a string looks like a valid e-mail address, however the function is always returning false regardless of what I type

function looksLikeMail(str) {
      var patt = new RegExp(/^(([^<>()\[\]\.,;:\s@\"]+(\.[^<>()\[\]\.,;:\s@\"]+)*)|(\".+\"))@(([^<>()[\]\.,;:\s@\"]+\.)+[^<>()[\]\.,;:\s@\"]{2,})$/i);
      return patt.test(str);
    }

var c1;
var c2;
var error = false;
c1 = document.getElementById("t8").value;
c2 = document.getElementById("t9").value;
if (document.getElementById("t8").value != "" || document.getElementById("t9").value != ""){
     if (document.getElementById("t8").value != ""){
     var validE;
     validE = looksLikeMail((String)(t8));
     if (!validE){
        error = true;
        alert("invalid email address");
       }
}

HTML

<div class="form-row">
  <label class="col align-self-center">&nbsp;<b>email (at least one)</b></label>
  </div>


  <div class="form-row">
  <div class="col-md-6 offset-md-3">
  <label for="inputEmail4">email-1</label>
  <input type="email" class="form-control" id="t8" placeholder="email">
  </div>

  <div class="col-md-6 offset-md-3">
  <label for="inputEmail5">email-2</label>
  <input type="email" class="form-control" id="t9" placeholder="email">
  </div>
  </div>

Seems to work for me: codepen.io/anon/pen/bJzwOR?editors=1111 What valid email address do you have problems with? — Sarah Groß
– Sarah Groß, Commented Apr 26, 2019 at 15:47
Use either the RegExp constructor or regexp literal syntax. — Pointy
– Pointy, Commented Apr 26, 2019 at 15:51
Why do you assign the variables c1 and c2, but then not use them? — Barmar
– Barmar, Commented Apr 26, 2019 at 15:58

junvar · Accepted Answer · 2019-04-26 15:49:49Z

1

Your looksLikeMail is fine (returns true for '[email protected]').

The rest of your JS though seems problematic. For one, your variable t8 is never defined. Also, (String) is invalid syntax. To cast in JS, you could do String(t8) instead. That being said, this is unnecessary because input.value will return a string anyways.

Since you seem unfamiliar with JS, i've done some small cleanup as well:

let t8 = document.getElementById("t8").value;
if (t8) {
     let validE = looksLikeMail(t8);
     if (!validE){
        error = true;
        alert("invalid email address");
     }
}

answered Apr 26, 2019 at 15:49

junvar

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Comments

Rolly · Accepted Answer · 2019-04-26 15:59:36Z

0

Try this code

        function looksLikeMail(str){
            var regex = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
            return regex.test(str);
        }

        looksLikeMail("[email protected]");// true
        looksLikeMail("[email protected]");// false
        looksLikeMail("[email protected]");// true

Also you can test the regex here

https://regex101.com/r/777dwJ/1

Regex credits to. https://stackoverflow.com/a/46181/5708097

edited Apr 26, 2019 at 15:59

answered Apr 26, 2019 at 15:56

Rolly

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3 Comments

Barmar Over a year ago

You should explain what you changed and how it solves the problem.

Rolly Over a year ago

well, basically im using another regex pattern

Barmar Over a year ago

Don't make this a challenge to find the difference. Explain what's wrong with his pattern.

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