function onProductInShopingCartDel() {
    return confirm("Are you sure you want to delete selected product from your shoping basket?");
}

function onCouponInShopingCartDel() {
    return confirm("Are you sure you want to delete selected coupon from your shoping basket?");
}

function onProductPlus(textbox) {
    try
    {
        var tb = document.getElementById(textbox);
        var value = parseInt(tb.value);
        
        value = value+1;
        
        tb.value = value;        
    }
    catch (err)
    {
        alert('Invalid value specified.');
    }
}

function onProductMinus(textbox) {
    try {
        var tb = document.getElementById(textbox);
        var value = parseInt(tb.value);

        value = value - 1;
        if (value < 0) value = 0;

        tb.value = value;
    }
    catch (err) {
        alert('Invalid value specified.');
    }
}