function showHelpYou(id) {
	swapDisplay('help-you-cont', "block");
	swapDisplay('help-you-item', "none");	
}
function openMenuItem(obj, id) {
	if(obj.className=="block") {
		obj.className = "block-open";
		swapDisplay(id, "block");
	} else {
		obj.className = "block";
		swapDisplay(id, "none");		
	}
}
function show(id) {
		display = document.getElementById(id).style.display;
		if(display=="") display = "none";
		
		if(display == "none") {swapDisplay(id, "block"); return;}
		if(display == "block") {swapDisplay(id, "none"); return;}		
}
function swapDisplay(id, display) {
	if(document.getElementById(id) == null) return false;
	document.getElementById(id).style.display = display;
}

 function checkEmail(){
    re = new RegExp("^[_a-zA-Z0-9\.\-]+@[_a-zA-Z0-9\.\-]+\.[a-zA-Z]{2,4}$");
    if (!re.test(document.getElementById("email").value)) {
      window.alert("Emailová adresa nemá správný formát");
      return false;
    } else {
    return true;
    }
}