scrollIntoView fixed navbar

Question

I have a framework7 based webapp From itemdetail.php?item=157 I created a back link in which I pass the id of the item to a list of all my items :

shop.php?item=157

On the shop.php page (which is a dynamic list of Items) I need to go to the specific item from the previous page :

function getUrlVars() {
    var vars = {};
    var parts =
        window.location.href.replace(/[?&]+([^=&]+)=([^&]*)/gi,
            function(m, key, value) {
                vars[key] = value;
            });
    return vars;
}
var
    itemid = getUrlVars()["item"];
if (itemid > 0) {
    var lastitem =
        document.getElementById(itemid);
    lastitem.scrollIntoView();
}

THis code is working BUT... The problem is that my fixed navbar of shop.php moves a down for few but The buttons inside the navbar become difficult to use and it is not possible to scrool up anymore... How to prevent the navbar this move ?