var actualPanelId = 'panel1';
var actualMenuTabId = 'tab1';

function showPanel(idnumber) {
document.getElementById('panel'+idnumber).style.display = 'block';
actualPanelId = 'panel'+idnumber;
document.getElementById('tab'+idnumber).className = 'vybrana-zalozka';
actualMenuTabId = 'tab'+idnumber;
}

function hidePanel(idnumber) {
document.getElementById('panel'+idnumber).style.display = 'none';
actualPanelId = 'panel'+idnumber;
document.getElementById('tab'+idnumber).className = 'vybrana-zalozka';
actualMenuTabId = 'tab'+idnumber;
}