function openAlertWindow() {
    
    var cover = document.getElementById("cover");
    cover.style.display = "block";

    cover.style.width = parseInt(document.body.clientWidth)+"px";
    cover.style.height = parseInt(document.body.clientHeight)+"px";

    var hidden = document.getElementById("galerie");
    hidden.style.display = "block";

    hidden.style.left = parseInt(((document.documentElement.clientWidth/2) - (hidden.clientWidth/2)) + document.documentElement.scrollLeft)+"px";
    hidden.style.top = parseInt(((document.documentElement.clientHeight/2) - (hidden.clientHeight/2)) + document.documentElement.scrollTop)+"px";
}

function closeAlertWindow() {
    var cover = document.getElementById("cover");
    cover.style.display = "none";
    
    var hidden = document.getElementById("galerie");
    hidden.style.display = "none";
}


function switchform1(){
	document.getElementById('form_zakaznik').style.display="block";
    document.getElementById('form_produkt').style.display="none";
};

function switchform2(){
	document.getElementById('form_zakaznik').style.display="none";
    document.getElementById('form_produkt').style.display="block";
};