Untitled

document.getElementById('mec_field_book_text_1').addEventListener('input', function (e) {
    if (this.value.length > 11) {
        this.value = this.value.slice(0, 11); // Trim to 11 characters
    }
});

document.getElementById('mec_book_form24455').addEventListener('submit', function (e) {
    const oib = document.getElementById('oib').value;
    if (oib.length !== 11) {
        alert('OIB must be exactly 11 characters long.');
        e.preventDefault();
    }
});