detectBrowser();

function detectBrowser(){
  if(navigator.appName == "Microsoft Internet Explorer"){
    if(getInternetExplorerVersion() <= 6 && !readCookie('oldBrowserAlert')){
      createCookie('oldBrowserAlert', true);
      alert("Stránka se vzhledem ke staré verzi Vašeho prohlížeče zobrazí posunutá. Doporučujeme stáhnout aktuální verzi.");
    }
  }
}


function getInternetExplorerVersion(){
  // Returns the version of Internet Explorer or a -1
  // (indicating the use of another browser).
  var rv = -1; // Return value assumes failure.
  if (navigator.appName == 'Microsoft Internet Explorer'){
    var ua = navigator.userAgent;
    var re  = new RegExp("MSIE ([0-9]{1,}[\.0-9]{0,})");
    if (re.exec(ua) != null)
      rv = parseFloat( RegExp.$1 );
  }
  return rv;
}

function createCookie(name,value,days) {
	if (days) {
		var date = new Date();
		date.setTime(date.getTime()+(days*24*60*60*1000));
		var expires = "; expires="+date.toGMTString();
	}
	else var expires = "";
	document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name) {
	var nameEQ = name + "=";
	var ca = document.cookie.split(';');
	for(var i=0;i < ca.length;i++) {
		var c = ca[i];
		while (c.charAt(0)==' ') c = c.substring(1,c.length);
		if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
	}
	return null;
}


//alert(getInternetExplorerVersion());