function getCookieVal(offset){

var endstr = document.cookie.indexOf (";", offset);

if(endstr == -1){ 
	endstr = document.cookie.length; 
}

return unescape(document.cookie.substring(offset, endstr));
}


function GetCookie (name) {

var arg = name + "=";
var alen = arg.length;
var clen = document.cookie.length;
var i = 0;

while(i < clen){

	var j = i + alen;

   if(document.cookie.substring(i, j) == arg){
      return getCookieVal(j);
   }

   i = document.cookie.indexOf(" ", i) + 1;

   if(i == 0) break; 
}

return null;
}


function IsAthorized(){

var el1 = document.getElementById('exit');
var el2 = document.getElementById('enter_block');

	if(GetCookie('usersesid')){

		if(el1 != null){

			el1.style.display = 'block';
         el2.style.display = 'none';
         document.getElementById('header_logout').style.display = 'block';
		 document.getElementById('header_login').style.display = 'none';

		}
	}

	else{


	   el1.style.display = 'none';
      el2.style.display = 'block';
      document.getElementById('header_login').style.display = 'block';
	  	document.getElementById('header_logout').style.display = 'none';

	}

}

function login_block() {

	var el = document.getElementById('login_block');

   IsAthorized();

	if( el.style.display != 'block' ){
		el.style.display = 'block';
	}
	else{
		el.style.display = 'none';
	}
}