//increase hodnoty pocet poloziek
function IncVal()
{
    var elem = document.getElementById('count');

    if ((!isNaN(elem.value)) && (elem.value < 4))
    {
        elem.value++;
    }
}

//decrease hodnoty pocet poloziek
function DecVal()
{
    var elem = document.getElementById('count');

    if ((!isNaN(elem.value)) && (elem.value > 1))
    {
        elem.value--;
    }
}

function CheckVal()
{
    var elem = document.getElementById('count');

    if ((!isNaN(elem.value)) && (elem.value > 4))
    {
        elem.value = 4;
    }
    if ((!isNaN(elem.value)) && (elem.value < 1))
    {
        elem.value = 1;
    }
}