function validateContactForm() {
    //validate name
    if ($("#name").val() == '') {
        showDialog('Chyba', 'Vyplňte prosím jméno', '#name');
        return false;
    }

    //validate email

    if ($("#email").val() == '') {
        showDialog('Chyba', 'Vyplňte prosím email', '#email');
        return false;
    }

    var regex = /^((([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+(\.([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+)*)|((\x22)((((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(([\x01-\x08\x0b\x0c\x0e-\x1f\x7f]|\x21|[\x23-\x5b]|[\x5d-\x7e]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(\\([\x01-\x09\x0b\x0c\x0d-\x7f]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))))*(((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(\x22)))@((([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.)+(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.?$/i;

    if ( regex.test($("#email").val()) == false ) {
        showDialog('Chyba', 'Vyplňte správně email', '#email');
        return false;
    }
    
    //validate msg
    if ($("#msg").val() == '') {
        showDialog('Chyba', 'Vyplňte prosím zprávu', '#msg');
        return false;
    }

    //validate captcha

    var ret;
    $.ajax({
        type: "POST",
        url:"/system/validate-captcha/",
        async: false,
        data: {
            captcha_word: $("#captcha_word").val(),
            captcha_id: $("#captcha_id").val()
        },
        dataType: "text",
        success: function(data){
            ret = data;
    }
    });

    if (ret != 'true') {
        showDialog('Chyba', 'Opíšte správně kód', '#captcha_word');
        return false;
    }

    return true;
   
}