//alias pre document.getElementById() aj s kontrolou
function byId(id){
	if(document.getElementById(id))
		return document.getElementById(id);
	else
		return false;	
}

function getViewportHeight(){
 var viewportheight;
 if (typeof window.innerWidth != 'undefined')
	viewportheight = window.innerHeight
 else if (typeof document.documentElement != 'undefined' && typeof document.documentElement.clientWidth != 'undefined' && document.documentElement.clientWidth != 0)
       viewportheight = document.documentElement.clientHeight
 else
       viewportheight = document.getElementsByTagName('body')[0].clientHeight;
 return viewportheight;   
}

function repositioning(){
	document.getElementById("container").style.marginTop = Math.max(0,(getViewportHeight()/2 - 363 ))+"px";
}

function focusform(){
	if(byId("login-username"))
		byId("login-username").focus();
}

function okPress(){
	byId("login-alert").style.display = "none";
	byId("ok-button").style.display = "none";
	byId("login-submit").style.display = "";
}

//kvoli IE
function initLogin(){
	var inputs = document.getElementsByTagName("input");
	for(var i=0;i<inputs.length;i++){
		inputs[i].onclick = function(){inputs[i].focus()};
	}
}

function urlencode(s) {
  s = encodeURIComponent(s);
  return s.replace(/~/g,'%7E').replace(/%20/g,'+');
 }

function doIfEnter(e,code){
var key;
if(window.event)
	key=window.event.keyCode; 
else 
	key=e.which;
if(key == 13)
	eval(code);
}