function top_menu(id) {

for (i=1;i<=4;i++) {
if (i != id) {
document.getElementById('top-sub-menu-'+i).style.visibility = 'hidden';
}
}

document.getElementById('top-sub-menu-'+id).style.visibility = 'visible';

}



function chart_pak_to_m2(n) {
original =  document.getElementById('productpak').value*n;
document.getElementById('productm2').value = Math.round(original*100)/100;
}

function chart_m2_to_pak(n) {

var m2 = document.getElementById('productm2').value;
var m2 = m2.replace(/,/g, ".");
var m2 = m2/n;



document.getElementById('productpak').value =  Math.ceil(m2);
}

function chart_lw_to_pak(n) {

l = document.getElementById('product_l').value;
w = document.getElementById('product_w').value; 

var l = l.replace(/,/g, ".");
var w = w.replace(/,/g, ".");


if (l != '' && w != '') {

m2 = l * w; 

if (document.getElementById('product_procent').checked) {
m2p = 10*(m2 / 100);
m2 = m2+m2p;
}

document.getElementById('productm2').value = Math.round(m2*100)/100;
document.getElementById('product_m2').value = Math.round(m2*100)/100;

chart_m2_to_pak(n);

}

}