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.

Answer 1

Using plain-JavaScript, I'd suggest:

function space(el, after) {
    // defaults to a space after 4 characters:
    after = after || 4;

    /* removes all characters in the value that aren't a number,
       or in the range from A to Z (uppercase): */
    var v = el.value.replace(/[^\dA-Z]/g, ''),
    /* creating the regular expression, to allow for the 'after' variable
       to be used/changed: */
        reg = new RegExp(".{" + after + "}","g")
    el.value = v.replace(reg, function (a, b, c) {
        return a + ' ';
    });
}

var el = document.getElementById('iban');
el.addEventListener('keyup', function () {
    space(this, 4);
});

JS Fiddle demo.

Somewhat belatedly, my rewrite of the above to handle strings, rather than DOM nodes:

function space(str, after) {
    if (!str) {
        return false;
    }
    after = after || 4;
    var v = str.replace(/[^\dA-Z]/g, ''),
        reg = new RegExp(".{" + after + "}", "g");
    return v.replace(reg, function (a) {
        return a + ' ';
    });
}

var el = document.getElementById('iban');
el.addEventListener('keyup', function () {
    this.value = space(this.value, 4);
});

JS Fiddle demo.

References:

• addEventListener().
• JavaScript regular expressions.