javascript - How to insert space every 4 characters for IBAN registering?

Question

I'm really new in JavaScript and I would like to add to my input text, space insertion for IBAN account registering.

<input type="text" name="iban" onkeyup="if(this.value.length > 34){this.value=this.value.substr(0, 34);}" />

Answer 1

The existing answers are relatively long, and they look like over-kill. Plus they don't work completely (for instance, one issue is that you can't edit previous characters).

For those interested, according to Wikipedia:

Permitted IBAN characters are the digits 0 to 9 and the 26 upper-case Latin alphabetic characters A to Z.

Here is a relatively short version that is similar to the existing answers:

document.getElementById('iban').addEventListener('input', function (e) {
  e.target.value = e.target.value.replace(/[^dA-Z]/g, '').replace(/(.{4})/g, '$1 ').trim();
});

<label for="iban">iban</label>
<input id="iban" type="text" name="iban" />