/**
     * Control search button
     */
    
    function controlSearchButton() {

        var search = $('searchText');

        if (search.value!='' && search.value.length>=3 && search.value!='zadajte hľadaný výraz') {
            return true;
        } else {
            return false;
        }

    }

    
    /**
     * Show & control value in search input field
     */

    function controlSearchInput(input) {

        if(input.value == 'zadajte hľadaný výraz') {
            input.value = '';
        } else if(input.value=='') {
            input.value = 'zadajte hľadaný výraz';
        }

    }
        

    /**
     * Change product number on size change
     */

    function changeProductNumber(numbers) {

        var size = $('size').value;
       
        $('numberLabel').update('Číslo produktu: '+numbers[size]).innerHTML;

    }
    

    /**
     * Check cart form
     */
    
    function checkCartForm() {

        var form = $('cart');
        var buttons = form.getInputs('radio', 'payment_type')

        if(buttons[0].checked == false && buttons[1].checked == false && buttons[2].checked == false) {
            alert('Vyberte si spôsob platby.');
            return false;
        } else return true;
    }
    

    /**
     * Check email input
     */
    
    function checkMail() {

        var input = $('email');

        if (!input.value.match((/^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$/))) {
            alert('Zadajte emailovú adresu.');
            return false;
        } else return true;

    }

    
   /**
     * Check agreement
     */
    
    function checkAgreement() {

        var agree = $('agreement');

        if(agree.checked == false) {
            alert('Musíte súhlasiť so všeobecnými obchodnými podmienkami a reklamačným poriadkom.');
            return false;
        } else return true;

    }
    

   /**
     * Open popup window
     */    

    function openW(urlW, width_w, height_w) {

        center_x = Math.round((window.screen.availWidth - width_w) / 2);
        center_y = Math.round((window.screen.availHeight - height_w) / 2);
        
        window.open(urlW,'_blank','top=' + center_y + ',left=' + center_x + ',width=' + width_w + ',height=' + height_w + ',status=no,titlebar=no,toolbar=no,menubar=no,location=no,resizable=yes,directories=no,scrollbars=yes');
    }